diff --git a/filter/algebra/classes/text_filter.php b/filter/algebra/classes/text_filter.php
index 56fe83566eb..3e308408a72 100644
--- a/filter/algebra/classes/text_filter.php
+++ b/filter/algebra/classes/text_filter.php
@@ -39,7 +39,7 @@ use stdClass;
  * You will then need to edit your moodle/config.php to invoke mathml_filter.php
  * -------------------------------------------------------------------------
  *
- * @package    filter
+ * @package    filter_algebra
  * @subpackage algebra
  * @copyright  2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
  *             Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
@@ -50,39 +50,22 @@ class text_filter extends \core_filters\text_filter {
     public function filter($text, array $options = []) {
         global $CFG, $DB;
 
-        /// Do a quick check using stripos to avoid unnecessary wor
-        if (!preg_match('/<algebra/i',$text) && !strstr($text,'@@')) {
+        // Do a quick check using stripos to avoid unnecessary work.
+        if (!preg_match('/<algebra/i', $text) && !strstr($text, '@@')) {
             return $text;
         }
 
-//restrict filtering to forum 130 (Maths Tools on moodle.org)
-#    $scriptname = $_SERVER['SCRIPT_NAME'];
-#    if (!strstr($scriptname,'/forum/')) {
-#        return $text;
-#    }
-#    if (strstr($scriptname,'post.php')) {
-#        $parent = forum_get_post_full($_GET['reply']);
-#        $discussion = $DB->get_record("forum_discussions",array("id"=>$parent->discussion));
-#    } else if (strstr($scriptname,'discuss.php')) {
-#        $discussion = $DB->get_record("forum_discussions",array("id"=>$_GET['d']));
-#    } else {
-#        return $text;
-#    }
-#    if ($discussion->forum != 130) {
-#        return $text;
-#    }
-
-        preg_match_all('/@(@@+)([^@])/',$text,$matches);
-        for ($i=0;$i<count($matches[0]);$i++) {
-            $replacement = str_replace('@','&#x00040;',$matches[1][$i]).$matches[2][$i];
-            $text = str_replace($matches[0][$i],$replacement,$text);
+        preg_match_all('/@(@@+)([^@])/', $text, $matches);
+        for ($i = 0; $i < count($matches[0]); $i++) {
+            $replacement = str_replace('@', '&#x00040;', $matches[1][$i]) . $matches[2][$i];
+            $text = str_replace($matches[0][$i], $replacement, $text);
         }
 
+        // The following regular expression matches TeX expressions delimited by:
         // <algebra> some algebraic input expression </algebra>
-        // or @@ some algebraic input expression @@
-
+        // or @@ some algebraic input expression @@.
         preg_match_all('/<algebra>(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches);
-        for ($i=0; $i<count($matches[0]); $i++) {
+        for ($i = 0; $i < count($matches[0]); $i++) {
             $algebra = $matches[1][$i] . $matches[2][$i];
 
             // Look for some common false positives, and skip processing them.
@@ -95,109 +78,113 @@ class text_filter extends \core_filters\text_filter {
                 continue;
             }
 
-            $algebra = str_replace('<nolink>','',$algebra);
-            $algebra = str_replace('</nolink>','',$algebra);
-            $algebra = str_replace('<span class="nolink">','',$algebra);
-            $algebra = str_replace('</span>','',$algebra);
+            $algebra = str_replace('<nolink>', '', $algebra);
+            $algebra = str_replace('</nolink>', '', $algebra);
+            $algebra = str_replace('<span class="nolink">', '', $algebra);
+            $algebra = str_replace('</span>', '', $algebra);
             $align = "middle";
-            if (preg_match('/^align=bottom /',$algebra)) {
-              $align = "text-bottom";
-              $algebra = preg_replace('/^align=bottom /','',$algebra);
-            } else if (preg_match('/^align=top /',$algebra)) {
-              $align = "text-top";
-              $algebra = preg_replace('/^align=top /','',$algebra);
+            if (preg_match('/^align=bottom /', $algebra)) {
+                $align = "text-bottom";
+                $algebra = preg_replace('/^align=bottom /', '', $algebra);
+            } else if (preg_match('/^align=top /', $algebra)) {
+                $align = "text-top";
+                $algebra = preg_replace('/^align=top /', '', $algebra);
             }
-            $md5 =  md5($algebra);
-            $filename =  $md5  . ".gif";
-            if (! $texcache = $DB->get_record("cache_filters",array("filter"=>"algebra", "md5key"=>$md5))) {
-               $algebra = str_replace('&lt;','<',$algebra);
-               $algebra = str_replace('&gt;','>',$algebra);
-               $algebra = str_replace('<>','#',$algebra);
-               $algebra = str_replace('<=','%',$algebra);
-               $algebra = str_replace('>=','!',$algebra);
-               $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
-               $algebra = str_replace('delta','zdelta',$algebra);
-               $algebra = str_replace('beta','bita',$algebra);
-               $algebra = str_replace('theta','thita',$algebra);
-               $algebra = str_replace('zeta','zita',$algebra);
-               $algebra = str_replace('eta','xeta',$algebra);
-               $algebra = str_replace('epsilon','zepslon',$algebra);
-               $algebra = str_replace('upsilon','zupslon',$algebra);
-               $algebra = preg_replace('!\r\n?!',' ',$algebra);
-               $algebra = escapeshellarg($algebra);
-               if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
-                  $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
-               } else {
-                  $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
-               }
-               $texexp = `$cmd`;
-               if (preg_match('/parsehilight/',$texexp)) {
-                 $text = str_replace( $matches[0][$i],"<b>Syntax error:</b> " . $texexp,$text);
-               } else if ($texexp) {
-                  $texexp = str_replace('zeroplace','',$texexp);
-                  $texexp = str_replace('#','\not= ',$texexp);
-                  $texexp = str_replace('%','\leq ',$texexp);
-                  $texexp = str_replace('!','\geq ',$texexp);
-                  $texexp = str_replace('\left{','{',$texexp);
-                  $texexp = str_replace('\right}','}',$texexp);
-                  $texexp = str_replace('\fun',' ',$texexp);
-                  $texexp = str_replace('infty','\infty',$texexp);
-                  $texexp = str_replace('alpha','\alpha',$texexp);
-                  $texexp = str_replace('gamma','\gamma',$texexp);
-                  $texexp = str_replace('iota','\iota',$texexp);
-                  $texexp = str_replace('kappa','\kappa',$texexp);
-                  $texexp = str_replace('lambda','\lambda',$texexp);
-                  $texexp = str_replace('mu','\mu',$texexp);
-                  $texexp = str_replace('nu','\nu',$texexp);
-                  $texexp = str_replace('xi','\xi',$texexp);
-                  $texexp = str_replace('rho','\rho',$texexp);
-                  $texexp = str_replace('sigma','\sigma',$texexp);
-                  $texexp = str_replace('tau','\tau',$texexp);
-                  $texexp = str_replace('phi','\phi',$texexp);
-                  $texexp = str_replace('chi','\chi',$texexp);
-                  $texexp = str_replace('psi','\psi',$texexp);
-                  $texexp = str_replace('omega','\omega',$texexp);
-                  $texexp = str_replace('zdelta','\delta',$texexp);
-                  $texexp = str_replace('bita','\beta',$texexp);
-                  $texexp = str_replace('thita','\theta',$texexp);
-                  $texexp = str_replace('zita','\zeta',$texexp);
-                  $texexp = str_replace('xeta','\eta',$texexp);
-                  $texexp = str_replace('zepslon','\epsilon',$texexp);
-                  $texexp = str_replace('zupslon','\upsilon',$texexp);
-                  $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
-                  $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
-                  $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
-                  //$texexp = preg_replace('/\\\frac{(.+?)}{\\\left\((.+?)\\\right\)}/s','\frac{'."\$1}{\$2}",$texexp);
-                  $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
-                  $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
-                  $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
-                  $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
-                  $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
-                  $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
-                  $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
-                  // Remove a forbidden keyword.
-                  $texexp = str_replace('\mbox', '', $texexp);
-                  $texcache = new stdClass();
-                  $texcache->filter = 'algebra';
-                  $texcache->version = 1;
-                  $texcache->md5key = $md5;
-                  $texcache->rawtext = $texexp;
-                  $texcache->timemodified = time();
-                  $DB->insert_record("cache_filters", $texcache, false);
-                  $text = str_replace( $matches[0][$i], self::get_image_markup($filename, $texexp, '', '', $align), $text);
-               } else {
-                  $text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> " . $matches[0][$i], $text);
-               }
+
+            $md5 = md5($algebra);
+            $filename = $md5  . ".gif";
+            if (! $texcache = $DB->get_record("cache_filters", ["filter" => "algebra", "md5key" => $md5])) {
+                $algebra = str_replace('&lt;', '<', $algebra);
+                $algebra = str_replace('&gt;', '>', $algebra);
+                $algebra = str_replace('<>', '#', $algebra);
+                $algebra = str_replace('<=', '%', $algebra);
+                $algebra = str_replace('>=', '!', $algebra);
+                $algebra = preg_replace('/([=><%!#] *)-/', "\$1 zeroplace -", $algebra);
+                $algebra = str_replace('delta', 'zdelta', $algebra);
+                $algebra = str_replace('beta', 'bita', $algebra);
+                $algebra = str_replace('theta', 'thita', $algebra);
+                $algebra = str_replace('zeta', 'zita', $algebra);
+                $algebra = str_replace('eta', 'xeta', $algebra);
+                $algebra = str_replace('epsilon', 'zepslon', $algebra);
+                $algebra = str_replace('upsilon', 'zupslon', $algebra);
+                $algebra = preg_replace('!\r\n?!', ' ', $algebra);
+                $algebra = escapeshellarg($algebra);
+                if ((PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
+                    $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
+                } else {
+                    $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
+                }
+                $texexp = `$cmd`;
+                if (preg_match('/parsehilight/', $texexp)) {
+                    $text = str_replace($matches[0][$i], "<b>Syntax error:</b> " . $texexp, $text);
+                } else if ($texexp) {
+                    $texexp = str_replace('zeroplace', '', $texexp);
+                    $texexp = str_replace('#', '\not= ', $texexp);
+                    $texexp = str_replace('%', '\leq ', $texexp);
+                    $texexp = str_replace('!', '\geq ', $texexp);
+                    $texexp = str_replace('\left{', '{', $texexp);
+                    $texexp = str_replace('\right}', '}', $texexp);
+                    $texexp = str_replace('\fun', ' ', $texexp);
+                    $texexp = str_replace('infty', '\infty', $texexp);
+                    $texexp = str_replace('alpha', '\alpha', $texexp);
+                    $texexp = str_replace('gamma', '\gamma', $texexp);
+                    $texexp = str_replace('iota', '\iota', $texexp);
+                    $texexp = str_replace('kappa', '\kappa', $texexp);
+                    $texexp = str_replace('lambda', '\lambda', $texexp);
+                    $texexp = str_replace('mu', '\mu', $texexp);
+                    $texexp = str_replace('nu', '\nu', $texexp);
+                    $texexp = str_replace('xi', '\xi', $texexp);
+                    $texexp = str_replace('rho', '\rho', $texexp);
+                    $texexp = str_replace('sigma', '\sigma', $texexp);
+                    $texexp = str_replace('tau', '\tau', $texexp);
+                    $texexp = str_replace('phi', '\phi', $texexp);
+                    $texexp = str_replace('chi', '\chi', $texexp);
+                    $texexp = str_replace('psi', '\psi', $texexp);
+                    $texexp = str_replace('omega', '\omega', $texexp);
+                    $texexp = str_replace('zdelta', '\delta', $texexp);
+                    $texexp = str_replace('bita', '\beta', $texexp);
+                    $texexp = str_replace('thita', '\theta', $texexp);
+                    $texexp = str_replace('zita', '\zeta', $texexp);
+                    $texexp = str_replace('xeta', '\eta', $texexp);
+                    $texexp = str_replace('zepslon', '\epsilon', $texexp);
+                    $texexp = str_replace('zupslon', '\upsilon', $texexp);
+                    $texexp = str_replace('\mbox{logten}', '\mbox{log}_{10}', $texexp);
+                    $texexp = str_replace('\mbox{acos}', '\mbox{cos}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{asin}', '\mbox{sin}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{atan}', '\mbox{tan}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{asec}', '\mbox{sec}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{acsc}', '\mbox{csc}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{acot}', '\mbox{cot}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{acosh}', '\mbox{cosh}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{asinh}', '\mbox{sinh}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{atanh}', '\mbox{tanh}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{asech}', '\mbox{sech}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{acsch}', '\mbox{csch}^{-1}', $texexp);
+                    $texexp = str_replace('\mbox{acoth}', '\mbox{coth}^{-1}', $texexp);
+                    $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s', '\sqrt[' . "\$2]{\$1}", $texexp);
+                    $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s', "|\$1|", $texexp);
+                    $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s', '\log_{' . "\$2}\\left(\$1\\right)", $texexp);
+                    $texexp = preg_replace(
+                        '/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',
+                        "\$1\$2^{" . "\$4}\\left(\$3\\right)",
+                        $texexp,
+                    );
+                    $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s', '\int_' . "{\$2}^{\$3}\$1 ", $texexp);
+                    $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s', '\int ' . "\$1 ", $texexp);
+                    $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s', '\lim_' . "{\$2\\to \$3}\$1 ", $texexp);
+                    // Remove a forbidden keyword.
+                    $texexp = str_replace('\mbox', '', $texexp);
+                    $texcache = new stdClass();
+                    $texcache->filter = 'algebra';
+                    $texcache->version = 1;
+                    $texcache->md5key = $md5;
+                    $texcache->rawtext = $texexp;
+                    $texcache->timemodified = time();
+                    $DB->insert_record("cache_filters", $texcache, false);
+                    $text = str_replace($matches[0][$i], filter_algebra_image($filename, $texexp, '', '', $align), $text);
+                } else {
+                    $text = str_replace($matches[0][$i], "<b>Undetermined error:</b> " . $matches[0][$i], $text);
+                }
             } else {
                 $text = str_replace($matches[0][$i], self::get_image_markup($filename, $texcache->rawtext), $text);
             }
@@ -251,7 +238,8 @@ class text_filter extends \core_filters\text_filter {
             }
             $anchorcontents .= "\" $style />";
 
-            if (!file_exists("$CFG->dataroot/filter/algebra/$imagefile") && has_capability('moodle/site:config', context_system::instance())) {
+            $imagefound = file_exists("$CFG->dataroot/filter/algebra/$imagefile");
+            if (!$imagefound && has_capability('moodle/site:config', context_system::instance())) {
                 $link = '/filter/algebra/algebradebug.php';
                 $action = null;
             } else {
diff --git a/filter/classes/external/get_all_states.php b/filter/classes/external/get_all_states.php
index 97116b0910b..fd995c44a8c 100644
--- a/filter/classes/external/get_all_states.php
+++ b/filter/classes/external/get_all_states.php
@@ -33,7 +33,6 @@ use context;
  * @since      Moodle 4.4
  */
 class get_all_states extends external_api {
-
     /**
      * Webservice parameters.
      *
@@ -85,24 +84,22 @@ class get_all_states extends external_api {
      * @return external_single_structure
      */
     public static function execute_returns(): external_single_structure {
-        return new external_single_structure(
-            [
-                'filters' => new external_multiple_structure(
-                    new external_single_structure(
-                        [
-                            'contextlevel' => new external_value(PARAM_ALPHA, 'The context level where the filters are:
-                                (coursecat, course, module).'),
-                            'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.'),
-                            'contextid' => new external_value(PARAM_INT, 'The context id.'),
-                            'filter'  => new external_value(PARAM_PLUGIN, 'Filter plugin name.'),
-                            'state' => new external_value(PARAM_INT, 'Filter state: 1 for on, -1 for off, -9999 if disabled.'),
-                            'sortorder' => new external_value(PARAM_INT, 'Execution order.'),
-                        ]
+        return new external_single_structure([
+            'filters' => new external_multiple_structure(
+                new external_single_structure([
+                    'contextlevel' => new external_value(
+                        PARAM_ALPHA,
+                        'The context level where the filters are: (coursecat, course, module).',
                     ),
-                    'All filters states'
-                ),
-                'warnings' => new external_warnings(),
-            ]
-        );
+                    'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.'),
+                    'contextid' => new external_value(PARAM_INT, 'The context id.'),
+                    'filter'  => new external_value(PARAM_PLUGIN, 'Filter plugin name.'),
+                    'state' => new external_value(PARAM_INT, 'Filter state: 1 for on, -1 for off, -9999 if disabled.'),
+                    'sortorder' => new external_value(PARAM_INT, 'Execution order.'),
+                ]),
+                'All filters states'
+            ),
+            'warnings' => new external_warnings(),
+        ]);
     }
 }
diff --git a/filter/classes/external/get_available_in_context.php b/filter/classes/external/get_available_in_context.php
index 84e78954b46..0c6e1229a8f 100644
--- a/filter/classes/external/get_available_in_context.php
+++ b/filter/classes/external/get_available_in_context.php
@@ -23,9 +23,6 @@
  */
 
 namespace core_filters\external;
-defined('MOODLE_INTERNAL') || die();
-
-require_once($CFG->libdir . '/filterlib.php');
 
 use core_external\external_api;
 use core_external\external_function_parameters;
@@ -49,19 +46,18 @@ class get_available_in_context extends external_api {
      * @since  Moodle 3.4
      */
     public static function execute_parameters() {
-        return new external_function_parameters (
-            array(
-                'contexts' => new external_multiple_structure(
-                    new external_single_structure(
-                        array(
-                            'contextlevel' => new external_value(PARAM_ALPHA, 'The context level where the filters are:
-                                (coursecat, course, module)'),
-                            'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.')
-                        )
-                    ), 'The list of contexts to check.'
-                ),
-            )
-        );
+        return new external_function_parameters([
+            'contexts' => new external_multiple_structure(
+                new external_single_structure([
+                    'contextlevel' => new external_value(
+                        PARAM_ALPHA,
+                        'The context level where the filters are: (coursecat, course, module)',
+                    ),
+                    'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.'),
+                ]),
+                'The list of contexts to check.'
+            ),
+        ]);
     }
 
     /**
@@ -72,8 +68,12 @@ class get_available_in_context extends external_api {
      * @since Moodle 3.4
      */
     public static function execute($contexts) {
-        $params = self::validate_parameters(self::get_available_in_context_parameters(), array('contexts' => $contexts));
-        $filters = $warnings = array();
+        global $CFG;
+
+        require_once($CFG->libdir . '/filterlib.php');
+
+        $params = self::validate_parameters(self::execute_parameters(), ['contexts' => $contexts]);
+        $filters = $warnings = [];
 
         foreach ($params['contexts'] as $contextinfo) {
             try {
@@ -81,12 +81,12 @@ class get_available_in_context extends external_api {
                 self::validate_context($context);
                 $contextinfo['contextid'] = $context->id;
             } catch (Exception $e) {
-                $warnings[] = array(
+                $warnings[] = [
                     'item' => 'context',
                     'itemid' => $contextinfo['instanceid'],
                     'warningcode' => $e->getCode(),
                     'message' => $e->getMessage(),
-                );
+                ];
                 continue;
             }
             $contextfilters = filter_get_available_in_context($context);
@@ -96,10 +96,10 @@ class get_available_in_context extends external_api {
             }
         }
 
-        return array(
+        return [
             'filters' => $filters,
             'warnings' => $warnings,
-        );
+        ];
     }
 
     /**
@@ -109,24 +109,22 @@ class get_available_in_context extends external_api {
      * @since  Moodle 3.4
      */
     public static function execute_returns() {
-        return new external_single_structure(
-            array(
-                'filters' => new external_multiple_structure(
-                    new external_single_structure(
-                        array(
-                            'contextlevel' => new external_value(PARAM_ALPHA, 'The context level where the filters are:
-                                (coursecat, course, module).'),
-                            'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.'),
-                            'contextid' => new external_value(PARAM_INT, 'The context id.'),
-                            'filter'  => new external_value(PARAM_PLUGIN, 'Filter plugin name.'),
-                            'localstate' => new external_value(PARAM_INT, 'Filter state: 1 for on, -1 for off, 0 if inherit.'),
-                            'inheritedstate' => new external_value(PARAM_INT, '1 or 0 to use when localstate is set to inherit.'),
-                        )
+        return new external_single_structure([
+            'filters' => new external_multiple_structure(
+                new external_single_structure([
+                    'contextlevel' => new external_value(
+                        PARAM_ALPHA,
+                        'The context level where the filters are: (coursecat, course, module).',
                     ),
-                    'Available filters'
-                ),
-                'warnings' => new external_warnings(),
-            )
-        );
+                    'instanceid' => new external_value(PARAM_INT, 'The instance id of item associated with the context.'),
+                    'contextid' => new external_value(PARAM_INT, 'The context id.'),
+                    'filter'  => new external_value(PARAM_PLUGIN, 'Filter plugin name.'),
+                    'localstate' => new external_value(PARAM_INT, 'Filter state: 1 for on, -1 for off, 0 if inherit.'),
+                    'inheritedstate' => new external_value(PARAM_INT, '1 or 0 to use when localstate is set to inherit.'),
+                ]),
+                'Available filters'
+            ),
+            'warnings' => new external_warnings(),
+        ]);
     }
 }
diff --git a/filter/classes/filter_manager.php b/filter/classes/filter_manager.php
index 615c52d1d80..dfb315eeb38 100644
--- a/filter/classes/filter_manager.php
+++ b/filter/classes/filter_manager.php
@@ -36,22 +36,22 @@ class filter_manager {
      * @var text_filter[][] This list of active filters, by context, for filtering content.
      * An array contextid => ordered array of filter name => filter objects.
      */
-    protected $textfilters = array();
+    protected $textfilters = [];
 
     /**
      * @var text_filter[][] This list of active filters, by context, for filtering strings.
      * An array contextid => ordered array of filter name => filter objects.
      */
-    protected $stringfilters = array();
+    protected $stringfilters = [];
 
     /** @var array Exploded version of $CFG->stringfilters. */
-    protected $stringfilternames = array();
+    protected $stringfilternames = [];
 
     /** @var filter_manager Holds the singleton instance. */
     protected static $singletoninstance;
 
     /**
-     * Constructor. Protected. Use {@link instance()} instead.
+     * Constructor. Protected. Use {@see instance()} instead.
      */
     protected function __construct() {
         $this->stringfilternames = filter_get_string_filters();
@@ -65,7 +65,7 @@ class filter_manager {
     public static function instance() {
         global $CFG;
         if (is_null(self::$singletoninstance)) {
-            if (!empty($CFG->perfdebug) and $CFG->perfdebug > 7) {
+            if (!empty($CFG->perfdebug) && $CFG->perfdebug > 7) {
                 self::$singletoninstance = new performance_measuring_filter_manager();
             } else {
                 self::$singletoninstance = new self();
@@ -88,9 +88,9 @@ class filter_manager {
      * Unloads all filters and other cached information
      */
     protected function unload_all_filters() {
-        $this->textfilters = array();
-        $this->stringfilters = array();
-        $this->stringfilternames = array();
+        $this->textfilters = [];
+        $this->stringfilters = [];
+        $this->stringfilternames = [];
     }
 
     /**
@@ -100,8 +100,8 @@ class filter_manager {
      */
     protected function load_filters($context) {
         $filters = filter_get_active_in_context($context);
-        $this->textfilters[$context->id] = array();
-        $this->stringfilters[$context->id] = array();
+        $this->textfilters[$context->id] = [];
+        $this->stringfilters[$context->id] = [];
         foreach ($filters as $filtername => $localconfig) {
             $filter = $this->make_filter_object($filtername, $context, $localconfig);
             if (is_null($filter)) {
@@ -131,7 +131,7 @@ class filter_manager {
             return new $filterclass($context, $localconfig);
         }
 
-        $path = $CFG->dirroot .'/filter/'. $filtername .'/filter.php';
+        $path = $CFG->dirroot . '/filter/' . $filtername . '/filter.php';
         if (!is_readable($path)) {
             return null;
         }
@@ -148,13 +148,17 @@ class filter_manager {
     /**
      * Apply a list of filters to some content.
      * @param string $text
-     * @param moodle_text_filter[] $filterchain array filter name => filter object.
+     * @param text_filter[] $filterchain array filter name => filter object.
      * @param array $options options passed to the filters.
-     * @param array $skipfilters of filter names. Any filters that should not be applied to this text.
+     * @param null|array $skipfilters of filter names. Any filters that should not be applied to this text.
      * @return string $text
      */
-    protected function apply_filter_chain($text, $filterchain, array $options = array(),
-            array $skipfilters = null) {
+    protected function apply_filter_chain(
+        $text,
+        $filterchain,
+        array $options = [],
+        ?array $skipfilters = null
+    ) {
         if (!isset($options['stage'])) {
             $filtermethod = 'filter';
         } else if (in_array($options['stage'], ['pre_format', 'pre_clean', 'post_clean', 'string'], true)) {
@@ -208,15 +212,19 @@ class filter_manager {
      * @param string $text The text to filter
      * @param context $context the context.
      * @param array $options options passed to the filters
-     * @param array $skipfilters of filter names. Any filters that should not be applied to this text.
+     * @param null|array $skipfilters of filter names. Any filters that should not be applied to this text.
      * @return string resulting text
      */
-    public function filter_text($text, $context, array $options = array(),
-            array $skipfilters = null) {
+    public function filter_text(
+        $text,
+        $context,
+        array $options = [],
+        ?array $skipfilters = null
+    ) {
         $text = $this->apply_filter_chain($text, $this->get_text_filters($context), $options, $skipfilters);
         if (!isset($options['stage']) || $options['stage'] === 'post_clean') {
             // Remove <nolink> tags for XHTML compatibility after the last filtering stage.
-            $text = str_replace(array('<nolink>', '</nolink>'), '', $text);
+            $text = str_replace(['<nolink>', '</nolink>'], '', $text);
         }
         return $text;
     }
diff --git a/filter/classes/filter_object.php b/filter/classes/filter_object.php
index a1c2166ba3d..7181fc595ac 100644
--- a/filter/classes/filter_object.php
+++ b/filter/classes/filter_object.php
@@ -77,15 +77,18 @@ class filter_object {
      * list($linkobject->hreftagbegin, $linkobject->hreftagend, $linkobject->replacementphrase) =
      *         call_user_func_array($linkobject->replacementcallback, $linkobject->replacementcallbackdata);
      * so the return should be an array [$hreftagbegin, $hreftagend, $replacementphrase], the last of which may be null.
-     * @param array $replacementcallbackdata data to be passed to $replacementcallback (optional).
+     * @param null|array $replacementcallbackdata data to be passed to $replacementcallback (optional).
      */
-    public function __construct($phrase, $hreftagbegin = '<span class="highlight">',
-            $hreftagend = '</span>',
-            $casesensitive = false,
-            $fullmatch = false,
-            $replacementphrase = null,
-            $replacementcallback = null,
-            array $replacementcallbackdata = null) {
+    public function __construct(
+        $phrase,
+        $hreftagbegin = '<span class="highlight">',
+        $hreftagend = '</span>',
+        $casesensitive = false,
+        $fullmatch = false,
+        $replacementphrase = null,
+        $replacementcallback = null,
+        ?array $replacementcallbackdata = null
+    ) {
 
         $this->phrase                  = $phrase;
         $this->hreftagbegin            = $hreftagbegin;
diff --git a/filter/classes/form/local_settings_form.php b/filter/classes/form/local_settings_form.php
index c736430d71d..88ce25a3cf1 100644
--- a/filter/classes/form/local_settings_form.php
+++ b/filter/classes/form/local_settings_form.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -17,6 +16,7 @@
 
 namespace core_filters;
 
+use core\context;
 use moodleform;
 
 defined('MOODLE_INTERNAL') || die();
@@ -27,19 +27,24 @@ require_once($CFG->libdir . '/formslib.php');
  * A Moodle form base class for editing local filter settings.
  *
  * @copyright Tim Hunt
- * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  * @package    core_filters
  */
 abstract class local_settings_form extends moodleform {
-    /** @var string The filter to manage */
-    protected $filter;
-
-    /** @var \core\context The context */
-    protected $context;
-
-    public function __construct($submiturl, $filter, $context) {
-        $this->filter = $filter;
-        $this->context = $context;
+    /**
+     * Create an instance of the form.
+     *
+     * @param string $submiturl
+     * @param string $filter
+     * @param context $context
+     */
+    public function __construct(
+        string $submiturl,
+        /** @var string The filter to manage */
+        protected string $filter,
+        /** @var \core\context The context */
+        protected context $context,
+    ) {
         parent::__construct($submiturl);
     }
 
@@ -63,7 +68,7 @@ abstract class local_settings_form extends moodleform {
     /**
      * Override this method to add your form controls.
      *
-     * @param $mform the form we are building. $this->_form, but passed in for convenience.
+     * @param \MoodleQuickForm $mform the form we are building. $this->_form, but passed in for convenience.
      */
     abstract protected function definition_inner($mform);
 
diff --git a/filter/classes/null_filter_manager.php b/filter/classes/null_filter_manager.php
index 018be83f4d2..f24759a1ab7 100644
--- a/filter/classes/null_filter_manager.php
+++ b/filter/classes/null_filter_manager.php
@@ -28,21 +28,25 @@ use core\context;
  */
 class null_filter_manager {
     /**
-     * As for the equivalent {@link filter_manager} method.
+     * As for the equivalent {@see filter_manager} method.
      *
      * @param string $text The text to filter
      * @param context $context not used.
      * @param array $options not used
-     * @param array $skipfilters not used
+     * @param null|array $skipfilters not used
      * @return string resulting text.
      */
-    public function filter_text($text, $context, array $options = array(),
-            array $skipfilters = null) {
+    public function filter_text(
+        $text,
+        $context,
+        array $options = [],
+        ?array $skipfilters = null
+    ) {
         return $text;
     }
 
     /**
-     * As for the equivalent {@link filter_manager} method.
+     * As for the equivalent {@see filter_manager} method.
      *
      * @param string $string The text to filter
      * @param context $context not used.
diff --git a/filter/classes/performance_measuring_filter_manager.php b/filter/classes/performance_measuring_filter_manager.php
index 12dc8969306..c712e78e8be 100644
--- a/filter/classes/performance_measuring_filter_manager.php
+++ b/filter/classes/performance_measuring_filter_manager.php
@@ -25,14 +25,15 @@ namespace core_filters;
  */
 class performance_measuring_filter_manager extends filter_manager {
     /** @var int number of filter objects created. */
-    protected $filterscreated = 0;
+    protected int $filterscreated = 0;
 
     /** @var int number of calls to filter_text. */
-    protected $textsfiltered = 0;
+    protected int $textsfiltered = 0;
 
     /** @var int number of calls to filter_string. */
-    protected $stringsfiltered = 0;
+    protected int $stringsfiltered = 0;
 
+    #[\Override]
     protected function unload_all_filters() {
         parent::unload_all_filters();
         $this->filterscreated = 0;
@@ -40,40 +41,51 @@ class performance_measuring_filter_manager extends filter_manager {
         $this->stringsfiltered = 0;
     }
 
+    #[\Override]
     protected function make_filter_object($filtername, $context, $localconfig) {
         $this->filterscreated++;
         return parent::make_filter_object($filtername, $context, $localconfig);
     }
 
-    public function filter_text($text, $context, array $options = array(),
-            array $skipfilters = null) {
+    #[\Override]
+    public function filter_text(
+        $text,
+        $context,
+        array $options = [],
+        ?array $skipfilters = null
+    ) {
         if (!isset($options['stage']) || $options['stage'] === 'post_clean') {
             $this->textsfiltered++;
         }
         return parent::filter_text($text, $context, $options, $skipfilters);
     }
 
+    #[\Override]
     public function filter_string($string, $context) {
         $this->stringsfiltered++;
         return parent::filter_string($string, $context);
     }
 
     /**
-     * Return performance information, in the form required by {@link get_performance_info()}.
+     * Return performance information, in the form required by {@see get_performance_info()}.
+     *
      * @return array the performance info.
      */
-    public function get_performance_summary() {
-        return array(array(
-            'contextswithfilters' => count($this->textfilters),
-            'filterscreated' => $this->filterscreated,
-            'textsfiltered' => $this->textsfiltered,
-            'stringsfiltered' => $this->stringsfiltered,
-        ), array(
-            'contextswithfilters' => 'Contexts for which filters were loaded',
-            'filterscreated' => 'Filters created',
-            'textsfiltered' => 'Pieces of content filtered',
-            'stringsfiltered' => 'Strings filtered',
-        ));
+    public function get_performance_summary(): array {
+        return [
+            [
+                'contextswithfilters' => count($this->textfilters),
+                'filterscreated' => $this->filterscreated,
+                'textsfiltered' => $this->textsfiltered,
+                'stringsfiltered' => $this->stringsfiltered,
+            ],
+            [
+                'contextswithfilters' => 'Contexts for which filters were loaded',
+                'filterscreated' => 'Filters created',
+                'textsfiltered' => 'Pieces of content filtered',
+                'stringsfiltered' => 'Strings filtered',
+            ],
+        ];
     }
 }
 
diff --git a/filter/classes/privacy/provider.php b/filter/classes/privacy/provider.php
index cd3132c8722..d0ec7375ffe 100644
--- a/filter/classes/privacy/provider.php
+++ b/filter/classes/privacy/provider.php
@@ -14,26 +14,16 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
+namespace core_filters\privacy;
+
 /**
- * Privacy Subsystem implementation for core_filters.
+ * Privacy Subsystem for core_filters implementing null_provider.
  *
  * @package    core_filters
  * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-
-namespace core_filters\privacy;
-
-defined('MOODLE_INTERNAL') || die();
-
-/**
- * Privacy Subsystem for core_filters implementing null_provider.
- *
- * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
 class provider implements \core_privacy\local\metadata\null_provider {
-
     /**
      * Get the language string identifier with the component's language
      * file to explain why this plugin stores no data.
diff --git a/filter/classes/text_filter.php b/filter/classes/text_filter.php
index f9914a3d91d..39acd05266d 100644
--- a/filter/classes/text_filter.php
+++ b/filter/classes/text_filter.php
@@ -74,7 +74,7 @@ abstract class text_filter {
      * @param array $options options passed to the filters
      * @return string the HTML content after the filtering has been applied.
      */
-    abstract public function filter($text, array $options = array());
+    abstract public function filter($text, array $options = []);
 
     /**
      * Filter text before changing format to HTML.
diff --git a/filter/data/classes/text_filter.php b/filter/data/classes/text_filter.php
index d5ccfbe6ddf..91996c92129 100644
--- a/filter/data/classes/text_filter.php
+++ b/filter/data/classes/text_filter.php
@@ -26,36 +26,32 @@ use core_filters\filter_object;
  */
 class text_filter extends \core_filters\text_filter {
     #[\Override]
-    public function filter($text, array $options = array()) {
+    public function filter($text, array $options = []) {
         global $CFG, $DB, $USER;
 
         // Trivial-cache - keyed on $cachedcourseid + $cacheduserid.
         static $cachedcourseid = null;
         static $cacheduserid = null;
-        static $coursecontentlist = array();
-        static $sitecontentlist = array();
+        static $coursecontentlist = [];
+        static $sitecontentlist = [];
 
         static $nothingtodo;
 
         // Try to get current course.
         $coursectx = $this->context->get_course_context(false);
-        if (!$coursectx) {
-            // We could be in a course category so no entries for courseid == 0 will be found.
-            $courseid = 0;
-        } else {
-            $courseid = $coursectx->instanceid;
-        }
+        // We could be in a course category so no entries for courseid == 0 will be found.
+        $courseid = $coursectx?->instanceid ?: 0;
 
         if ($cacheduserid !== $USER->id) {
             // Invalidate all caches if the user changed.
-            $coursecontentlist = array();
-            $sitecontentlist = array();
+            $coursecontentlist = [];
+            $sitecontentlist = [];
             $cacheduserid = $USER->id;
             $cachedcourseid = $courseid;
             $nothingtodo = false;
         } else if ($courseid != get_site()->id && $courseid != 0 && $cachedcourseid != $courseid) {
             // Invalidate course-level caches if the course id changed.
-            $coursecontentlist = array();
+            $coursecontentlist = [];
             $cachedcourseid = $courseid;
             $nothingtodo = false;
         }
@@ -65,6 +61,7 @@ class text_filter extends \core_filters\text_filter {
         }
 
         // If courseid == 0 only site entries will be returned.
+        $site = get_site();
         if ($courseid == get_site()->id || $courseid == 0) {
             $contentlist = & $sitecontentlist;
         } else {
@@ -73,12 +70,12 @@ class text_filter extends \core_filters\text_filter {
 
         // Create a list of all the resources to search for. It may be cached already.
         if (empty($contentlist)) {
-            $coursestosearch = $courseid ? array($courseid) : array(); // Add courseid if found
-            if (get_site()->id != $courseid) { // Add siteid if was not courseid
+            $coursestosearch = $courseid ? [$courseid] : []; // Add courseid if found.
+            if (get_site()->id != $courseid) { // Add siteid if was not courseid.
                 $coursestosearch[] = get_site()->id;
             }
-            // We look for text field contents only if have autolink enabled (param1)
-            list ($coursesql, $params) = $DB->get_in_or_equal($coursestosearch);
+            // We look for text field contents only if have autolink enabled (param1).
+            [$coursesql, $params] = $DB->get_in_or_equal($coursestosearch);
             $sql = 'SELECT dc.id AS contentid, dr.id AS recordid, dc.content AS content, d.id AS dataid
                       FROM {data} d
                       JOIN {data_fields} df ON df.dataid = d.id
@@ -94,7 +91,7 @@ class text_filter extends \core_filters\text_filter {
             }
 
             foreach ($contents as $key => $content) {
-                // Trim empty or unlinkable concepts
+                // Trim empty or unlinkable concepts.
                 $currentcontent = trim(strip_tags($content->content));
                 if (empty($currentcontent)) {
                     unset($contents[$key]);
@@ -103,7 +100,7 @@ class text_filter extends \core_filters\text_filter {
                     $contents[$key]->content = $currentcontent;
                 }
 
-                // Rule out any small integers.  See bug 1446
+                // Rule out any small integers.  See bug 1446.
                 $currentint = intval($currentcontent);
                 if ($currentint && (strval($currentint) == $currentcontent) && $currentint < 1000) {
                     unset($contents[$key]);
@@ -118,17 +115,24 @@ class text_filter extends \core_filters\text_filter {
             usort($contents, [self::class, 'sort_entries_by_length']);
 
             foreach ($contents as $content) {
-                $href_tag_begin = '<a class="data autolink dataid'.$content->dataid.'" title="'.s($content->content).'" '.
-                                  'href="'.$CFG->wwwroot.'/mod/data/view.php?d='.$content->dataid.
-                                  '&amp;rid='.$content->recordid.'">';
-                $contentlist[] = new filter_object($content->content, $href_tag_begin, '</a>', false, true);
+                $hrefopen = '<a class="data autolink dataid' . $content->dataid . '" title="' . s($content->content) . '" ' .
+                                  'href="' . $CFG->wwwroot . '/mod/data/view.php?d=' . $content->dataid .
+                                  '&amp;rid=' . $content->recordid . '">';
+                $contentlist[] = new filter_object($content->content, $hrefopen, '</a>', false, true);
             }
 
-            $contentlist = filter_remove_duplicates($contentlist); // Clean dupes
+            $contentlist = filter_remove_duplicates($contentlist); // Clean dupes.
         }
-        return filter_phrases($text, $contentlist);  // Look for all these links in the text
+        return filter_phrases($text, $contentlist);  // Look for all these links in the text.
     }
 
+    /**
+     * Helper to sort array values by content length.
+     *
+     * @param mixed $content0
+     * @param mixed $content1
+     * @return int
+     */
     private static function sort_entries_by_length($content0, $content1) {
         $len0 = strlen($content0->content);
         $len1 = strlen($content1->content);
diff --git a/filter/displayh5p/classes/text_filter.php b/filter/displayh5p/classes/text_filter.php
index 4996b11ed49..be53ee624d4 100644
--- a/filter/displayh5p/classes/text_filter.php
+++ b/filter/displayh5p/classes/text_filter.php
@@ -31,22 +31,14 @@ use core_h5p\local\library\autoloader;
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class text_filter extends \core_filters\text_filter {
-    /**
-     * @var boolean $loadresizerjs This is whether to request the resize.js script.
-     */
+    /** @var bool $loadresizerjs This is whether to request the resize.js script */
     private static $loadresizerjs = true;
 
-    /**
-     * Function filter replaces any h5p-sources.
-     *
-     * @param  string $text    HTML content to process
-     * @param  array  $options options passed to the filters
-     * @return string
-     */
-    public function filter($text, array $options = array()) {
+    #[\Override]
+    public function filter($text, array $options = []) {
         global $CFG, $USER;
 
-        if (!is_string($text) or empty($text)) {
+        if (!is_string($text) || empty($text)) {
             // Non string data can not be filtered anyway.
             return $text;
         }
@@ -60,18 +52,18 @@ class text_filter extends \core_filters\text_filter {
         $allowedsources = get_config('filter_displayh5p', 'allowedsources');
         $allowedsources = array_filter(array_map('trim', explode("\n", $allowedsources)));
 
-        $localsource = '('.preg_quote($CFG->wwwroot, '~').'/[^ &\#"\'<]*\.h5p([?][^ "\'<]*)?[^ \#"\'<]*)';
+        $localsource = '(' . preg_quote($CFG->wwwroot, '~') . '/[^ &\#"\'<]*\.h5p([?][^ "\'<]*)?[^ \#"\'<]*)';
         $allowedsources[] = $localsource;
 
-        $params = array(
+        $params = [
             'tagbegin' => '<iframe src="',
-            'tagend' => '</iframe>'
-        );
+            'tagend' => '</iframe>',
+        ];
 
         $specialchars = ['?', '&'];
         $escapedspecialchars = ['\?', '&amp;'];
-        $h5pcontents = array();
-        $h5plinks = array();
+        $h5pcontents = [];
+        $h5plinks = [];
 
         // Check all allowed sources.
         foreach ($allowedsources as $source) {
@@ -82,7 +74,7 @@ class text_filter extends \core_filters\text_filter {
             // only if the user has the proper capabilities.
             $params['canbeedited'] = (!empty($USER->editing)) && ($source == $localsource);
             if ($source == $localsource) {
-                $params['tagbegin'] = '<iframe src="'.$CFG->wwwroot.'/h5p/embed.php?url=';
+                $params['tagbegin'] = '<iframe src="' . $CFG->wwwroot . '/h5p/embed.php?url=';
                 $escapechars = $source;
                 $ultimatepattern = $source;
             } else {
@@ -100,17 +92,33 @@ class text_filter extends \core_filters\text_filter {
                 continue;
             }
 
-            $h5pcontenturl = new filter_object($source, null, null, false,
-                false, null, [$this, 'filterobject_prepare_replacement_callback'], $params + ['ish5plink' => false]);
+            $h5pcontenturl = new filter_object(
+                $source,
+                null,
+                null,
+                false,
+                false,
+                null,
+                [$this, 'filterobject_prepare_replacement_callback'],
+                $params + ['ish5plink' => false]
+            );
 
-            $h5pcontenturl->workregexp = '#'.$ultimatepattern.'#';
+            $h5pcontenturl->workregexp = '#' . $ultimatepattern . '#';
             $h5pcontents[] = $h5pcontenturl;
 
             // Regex to find h5p extensions in an <a> tag.
-            $linkregexp = '~<a [^>]*href=["\']('.$escapechars.'[^"\']*)["\'][^>]*>([^<]*)</a>~is';
+            $linkregexp = '~<a [^>]*href=["\'](' . $escapechars . '[^"\']*)["\'][^>]*>([^<]*)</a>~is';
 
-            $h5plinkurl = new filter_object($linkregexp, null, null, false,
-                false, null, [$this, 'filterobject_prepare_replacement_callback'], $params + ['ish5plink' => true]);
+            $h5plinkurl = new filter_object(
+                $linkregexp,
+                null,
+                null,
+                false,
+                false,
+                null,
+                [$this, 'filterobject_prepare_replacement_callback'],
+                $params + ['ish5plink' => true]
+            );
             $h5plinkurl->workregexp = $linkregexp;
             $h5plinks[] = $h5plinkurl;
         }
@@ -123,7 +131,8 @@ class text_filter extends \core_filters\text_filter {
         // Apply filter inside <a> tag href attribute.
         // We can not use filter_phrase function because it removes all tags and can not be applied in tag attributes.
         foreach ($h5plinks as $h5plink) {
-            $text = preg_replace_callback($h5plink->workregexp,
+            $text = preg_replace_callback(
+                $h5plink->workregexp,
                 function ($matches) use ($h5plink) {
                     if ($matches[1] == $matches[2]) {
                         filter_prepare_phrase_for_replacement($h5plink);
@@ -132,7 +141,9 @@ class text_filter extends \core_filters\text_filter {
                     } else {
                         return $matches[0];
                     }
-                }, $text);
+                },
+                $text
+            );
         }
 
         // The "Edit" button below each H5P content will be displayed only for users with permissions to edit the content (to
@@ -140,7 +151,8 @@ class text_filter extends \core_filters\text_filter {
         // As the H5P URL is required in order to get this information, this action can be done only here(the
         // prepare_replacement_callback method has only the placeholders).
         foreach ($h5pcontents as $h5pcontent) {
-            $text = preg_replace_callback($h5pcontent->workregexp,
+            $text = preg_replace_callback(
+                $h5pcontent->workregexp,
                 function ($matches) use ($h5pcontent) {
                     global $USER, $CFG;
 
@@ -153,7 +165,7 @@ class text_filter extends \core_filters\text_filter {
                         }
 
                         $contenturl = $matches[0];
-                        list($file, $h5p) = \core_h5p\api::get_original_content_from_pluginfile_url($contenturl, true, true);
+                        [$file, $h5p] = \core_h5p\api::get_original_content_from_pluginfile_url($contenturl, true, true);
                         if ($file) {
                             filter_prepare_phrase_for_replacement($h5pcontent);
 
@@ -178,7 +190,9 @@ class text_filter extends \core_filters\text_filter {
                     }
 
                     return $matches[0];
-                }, $text);
+                },
+                $text
+            );
         }
 
         $result = filter_phrases($text, $h5pcontents, null, null, false, true);
@@ -187,18 +201,21 @@ class text_filter extends \core_filters\text_filter {
         // embed.php page is requesting a PARAM_LOCALURL url parameter, so for files/directories use non-alphanumeric
         // characters, we need to encode the parameter. Fetch url parameter added to embed.php and encode the whole url.
         $localurl = '#\?url=([^" <]*[\/]+[^" <]*\.h5p)([?][^"]*)?#';
-        $result = preg_replace_callback($localurl,
+        $result = preg_replace_callback(
+            $localurl,
             function ($matches) {
                 $baseurl = rawurlencode($matches[1]);
                 // Deal with possible parameters in the url link.
                 if (!empty($matches[2])) {
                     $match = explode('?', $matches[2]);
                     if (!empty($match[1])) {
-                        $baseurl = $baseurl."&".$match[1];
+                        $baseurl = $baseurl . "&" . $match[1];
                     }
                 }
-                return "?url=".$baseurl;
-            }, $result);
+                return "?url=" . $baseurl;
+            },
+            $result
+        );
 
         return $result;
     }
@@ -214,7 +231,6 @@ class text_filter extends \core_filters\text_filter {
      * @return array [$hreftagbegin, $hreftagend, $replacementphrase] for filterobject.
      */
     public function filterobject_prepare_replacement_callback($tagbegin, $tagend, $urlmodifier, $canbeedited, $ish5plink) {
-
         $sourceurl = "$1";
         if ($urlmodifier !== "") {
             $sourceurl .= $urlmodifier;
diff --git a/filter/displayh5p/tests/text_filter_test.php b/filter/displayh5p/tests/text_filter_test.php
index ce843a89d1d..2c2b2dd459d 100644
--- a/filter/displayh5p/tests/text_filter_test.php
+++ b/filter/displayh5p/tests/text_filter_test.php
@@ -51,7 +51,6 @@ final class text_filter_test extends \advanced_testcase {
             'filter_displayh5p'
         );
 
-
         $filterplugin = new text_filter(null, []);
 
         $filteredtext = $filterplugin->filter($text);
@@ -59,7 +58,7 @@ final class text_filter_test extends \advanced_testcase {
     }
 
     /**
-     * Provides texts to filter for the {@link self::test_filter_urls} method.
+     * Provides texts to filter for the {@see self::test_filter_urls} method.
      *
      * @return array
      */
@@ -103,6 +102,7 @@ final class text_filter_test extends \advanced_testcase {
             ],
             [
                 "https://generic.wordpress.soton.ac.uk/altc/wp-admin/admin-ajax.php?action=h5p_embed&amp;id=13",
+                // phpcs:ignore moodle.Files.LineLength.TooLong
                 "#<iframe src=\"https://generic.wordpress.soton.ac.uk/altc/wp-admin/admin-ajax.php\?action=h5p_embed\&amp\;id=13\"[^>]+?>#",
             ],
             [
diff --git a/filter/emailprotect/classes/text_filter.php b/filter/emailprotect/classes/text_filter.php
index 8c4b3be8ce1..6a0c526a3e6 100644
--- a/filter/emailprotect/classes/text_filter.php
+++ b/filter/emailprotect/classes/text_filter.php
@@ -21,32 +21,29 @@ namespace filter_emailprotect;
  *
  * This class looks for email addresses in Moodle text and hides them using the Moodle obfuscate_text function.
  *
- * @package    filter
+ * @package    filter_emailprotect
  * @subpackage emailprotect
  * @copyright  2004 Mike Churchward
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class text_filter extends \core_filters\text_filter {
     #[\Override]
-    public function filter($text, array $options = array()) {
-    /// Do a quick check using stripos to avoid unnecessary work
+    public function filter($text, array $options = []) {
+        // Do a quick check using stripos to avoid unnecessary work.
         if (strpos($text, '@') === false) {
             return $text;
         }
 
-    /// There might be an email in here somewhere so continue ...
-        $matches = array();
-
-    /// regular expression to define a standard email string.
+        // Regular expression to define a standard email string.
         $emailregex = '((?:[\w\.\-])+\@(?:(?:[a-zA-Z\d\-])+\.)+(?:[a-zA-Z\d]{2,4}))';
 
-    /// pattern to find a mailto link with the linked text.
-        $pattern = '|(<a\s+href\s*=\s*[\'"]?mailto:)'.$emailregex.'([\'"]?\s*>)'.'(.*)'.'(</a>)|iU';
+        // Pattern to find a mailto link with the linked text.
+        $pattern = '|(<a\s+href\s*=\s*[\'"]?mailto:)' . $emailregex . '([\'"]?\s*>)' . '(.*)' . '(</a>)|iU';
         $text = preg_replace_callback($pattern, 'filter_emailprotect_alter_mailto', $text);
         $text = preg_replace_callback($pattern, [self::class, 'alter_mailto'], $text);
 
-    /// pattern to find any other email address in the text.
-        $pattern = '/(^|\s+|>)'.$emailregex.'($|\s+|\.\s+|\.$|<)/i';
+        // Pattern to find any other email address in the text.
+        $pattern = '/(^|\s+|>)' . $emailregex . '($|\s+|\.\s+|\.$|<)/i';
         $text = preg_replace_callback($pattern, 'filter_emailprotect_alter_email', $text);
         $text = preg_replace_callback($pattern, [self::class, 'alter_email'], $text);
 
diff --git a/filter/emoticon/classes/text_filter.php b/filter/emoticon/classes/text_filter.php
index 02c9f1b3b7a..329545191c2 100644
--- a/filter/emoticon/classes/text_filter.php
+++ b/filter/emoticon/classes/text_filter.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -34,7 +33,7 @@ class text_filter extends \core_filters\text_filter {
      * - dimension 2: theme.
      * @var array
      */
-    protected static $emoticontexts = array();
+    protected static $emoticontexts = [];
 
     /**
      * Internal cache used for replacing. Multidimensional array;
@@ -42,22 +41,14 @@ class text_filter extends \core_filters\text_filter {
      * - dimension 2: theme.
      * @var array
      */
-    protected static $emoticonimgs = array();
-
-    /**
-     * Apply the filter to the text
-     *
-     * @see \core_filters\filter_manager::apply_filter_chain()
-     * @param string $text to be processed by the text
-     * @param array $options filter options
-     * @return string text after processing
-     */
-    public function filter($text, array $options = array()) {
+    protected static $emoticonimgs = [];
 
+    #[\Override]
+    public function filter($text, array $options = []) {
         if (!isset($options['originalformat'])) {
-            // if the format is not specified, we are probably called by {@see format_string()}
+            // If the format is not specified, we are probably called by {@see format_string()}
             // in that case, it would be dangerous to replace text with the image because it could
-            // be stripped. therefore, we do nothing
+            // be stripped. therefore, we do nothing.
             return $text;
         }
         if (in_array($options['originalformat'], explode(',', get_config('filter_emoticon', 'formats')))) {
@@ -66,10 +57,6 @@ class text_filter extends \core_filters\text_filter {
         return $text;
     }
 
-    ////////////////////////////////////////////////////////////////////////////
-    // internal implementation starts here
-    ////////////////////////////////////////////////////////////////////////////
-
     /**
      * Replace emoticons found in the text with their images
      *
@@ -82,12 +69,12 @@ class text_filter extends \core_filters\text_filter {
         $lang = current_language();
         $theme = $PAGE->theme->name;
 
-        if (!isset(self::$emoticontexts[$lang][$theme]) or !isset(self::$emoticonimgs[$lang][$theme])) {
-            // prepare internal caches
+        if (!isset(self::$emoticontexts[$lang][$theme]) || !isset(self::$emoticonimgs[$lang][$theme])) {
+            // Prepare internal caches.
             $manager = get_emoticon_manager();
             $emoticons = $manager->get_emoticons();
-            self::$emoticontexts[$lang][$theme] = array();
-            self::$emoticonimgs[$lang][$theme] = array();
+            self::$emoticontexts[$lang][$theme] = [];
+            self::$emoticonimgs[$lang][$theme] = [];
             foreach ($emoticons as $emoticon) {
                 self::$emoticontexts[$lang][$theme][] = $emoticon->text;
                 self::$emoticonimgs[$lang][$theme][] = $OUTPUT->render($manager->prepare_renderable_emoticon($emoticon));
@@ -107,7 +94,7 @@ class text_filter extends \core_filters\text_filter {
         $exclude = 0;
 
         // Define the patterns that mark the start of the forbidden zones.
-        $excludepattern = array('/^<script/is', '/^<span[^>]+class="nolink[^"]*"/is', '/^<pre/is');
+        $excludepattern = ['/^<script/is', '/^<span[^>]+class="nolink[^"]*"/is', '/^<pre/is'];
 
         // Loop through the fragments.
         foreach ($processing as $fragment) {
@@ -122,20 +109,26 @@ class text_filter extends \core_filters\text_filter {
             }
             if ($exclude > 0) {
                 // If we are ignoring the fragment, then we must check if we may have reached the end of the zone.
-                if (strpos($fragment, '</span') !== false || strpos($fragment, '</script') !== false
-                    || strpos($fragment, '</pre') !== false) {
+                if (
+                    strpos($fragment, '</span') !== false || strpos($fragment, '</script') !== false
+                    || strpos($fragment, '</pre') !== false
+                ) {
                     $exclude -= 1;
                     // This is needed because of a double increment at the first element.
                     if ($exclude == 1) {
                         $exclude -= 1;
                     }
-                } else if (strpos($fragment, '<span') !== false || strpos($fragment, '<script') !== false
-                    || strpos($fragment, '<pre') !== false) {
+                } else if (
+                    strpos($fragment, '<span') !== false || strpos($fragment, '<script') !== false
+                    || strpos($fragment, '<pre') !== false
+                ) {
                     // If we find a nested tag we increase the exclusion level.
                     $exclude = $exclude + 1;
                 }
-            } else if (strpos($fragment, '<span') === false ||
-                       strpos($fragment, '</span') === false) {
+            } else if (
+                strpos($fragment, '<span') === false ||
+                       strpos($fragment, '</span') === false
+            ) {
                 // This is the meat of the code - this is run every time.
                 // This code only runs for fragments that are not ignored (including the tags themselves).
                 $fragment = str_replace(self::$emoticontexts[$lang][$theme], self::$emoticonimgs[$lang][$theme], $fragment);
diff --git a/filter/emoticon/tests/text_filter_test.php b/filter/emoticon/tests/text_filter_test.php
index f7514ec07ae..94fe29332cd 100644
--- a/filter/emoticon/tests/text_filter_test.php
+++ b/filter/emoticon/tests/text_filter_test.php
@@ -88,7 +88,7 @@ final class text_filter_test extends \advanced_testcase {
      *
      * @return  array
      */
-    public static function filter_emoticon_provider() {
+    public static function filter_emoticon_provider(): array {
         $grr = '(grr)';
         return [
             'FORMAT_MOODLE is not filtered' => [
@@ -191,11 +191,12 @@ final class text_filter_test extends \advanced_testcase {
     /**
      * Get a copy of the filter configured for testing.
      *
-     * @param array $args
+     * @param array ...$args
      * @return \filter_emoticon\text_filter
      */
     protected function get_testable_filter_emoticon(...$args): text_filter {
         return new class extends text_filter {
+            // phpcs:ignore moodle.Commenting.MissingDocblock.MissingTestcaseMethodDescription
             public function __construct(...$args) {
                 // Reset static emoticon caches.
                 parent::$emoticontexts = [];
diff --git a/filter/glossary/classes/text_filter.php b/filter/glossary/classes/text_filter.php
index d5c52820d02..6b5b0750a3f 100644
--- a/filter/glossary/classes/text_filter.php
+++ b/filter/glossary/classes/text_filter.php
@@ -23,6 +23,9 @@ use core\url;
 use core_filters\filter_object;
 use stdClass;
 
+// phpcs:disable moodle.NamingConventions.ValidVariableName.VariableNameLowerCase -- GLOSSARY_EXCLUDEENTRY
+// phpcs:disable moodle.NamingConventions.ValidVariableName.VariableNameUnderscore -- GLOSSARY_EXCLUDEENTRY
+
 /**
  * This filter provides automatic linking to glossary entries, aliases and categories when found inside every Moodle text.
  *
@@ -36,6 +39,7 @@ class text_filter extends \core_filters\text_filter {
     /** @var null|cache_store cache used to store the terms for this course. */
     protected $cache = null;
 
+    #[\Override]
     public function setup($page, $context) {
         if ($page->requires->should_create_one_time_item_now('filter_glossary_autolinker')) {
             $page->requires->js_call_amd('filter_glossary/autolinker', 'init', []);
@@ -72,7 +76,7 @@ class text_filter extends \core_filters\text_filter {
             return $cached->cacheconceptlist;
         }
 
-        list($glossaries, $allconcepts) = \mod_glossary\local\concept_cache::get_concepts($courseid);
+        [$glossaries, $allconcepts] = \mod_glossary\local\concept_cache::get_concepts($courseid);
 
         if (!$allconcepts) {
             $tocache = new stdClass();
@@ -83,13 +87,20 @@ class text_filter extends \core_filters\text_filter {
             return [];
         }
 
-        $conceptlist = array();
+        $conceptlist = [];
 
         foreach ($allconcepts as $concepts) {
             foreach ($concepts as $concept) {
-                $conceptlist[] = new filter_object($concept->concept, null, null,
-                        $concept->casesensitive, $concept->fullmatch, null,
-                        [$this, 'filterobject_prepare_replacement_callback'], [$concept, $glossaries]);
+                $conceptlist[] = new filter_object(
+                    $concept->concept,
+                    null,
+                    null,
+                    $concept->casesensitive,
+                    $concept->fullmatch,
+                    null,
+                    [$this, 'filterobject_prepare_replacement_callback'],
+                    [$concept, $glossaries]
+                );
             }
         }
 
@@ -120,30 +131,39 @@ class text_filter extends \core_filters\text_filter {
         global $CFG;
 
         if ($concept->category) { // Link to a category.
-            $title = get_string('glossarycategory', 'filter_glossary',
-                    ['glossary' => $glossaries[$concept->glossaryid], 'category' => $concept->concept]);
-            $link = new url('/mod/glossary/view.php',
-                    ['g' => $concept->glossaryid, 'mode' => 'cat', 'hook' => $concept->id]);
-            $attributes = array(
+            $title = get_string(
+                'glossarycategory',
+                'filter_glossary',
+                ['glossary' => $glossaries[$concept->glossaryid], 'category' => $concept->concept]
+            );
+            $link = new url(
+                '/mod/glossary/view.php',
+                ['g' => $concept->glossaryid, 'mode' => 'cat', 'hook' => $concept->id]
+            );
+            $attributes = [
                     'href'  => $link,
                     'title' => $title,
-                    'class' => 'glossary autolink category glossaryid' . $concept->glossaryid);
-
+                    'class' => 'glossary autolink category glossaryid' . $concept->glossaryid, ];
         } else { // Link to entry or alias.
-            $title = get_string('glossaryconcept', 'filter_glossary',
-                    ['glossary' => $glossaries[$concept->glossaryid], 'concept' => $concept->concept]);
+            $title = get_string(
+                'glossaryconcept',
+                'filter_glossary',
+                ['glossary' => $glossaries[$concept->glossaryid], 'concept' => $concept->concept]
+            );
             // Hardcoding dictionary format in the URL rather than defaulting
             // to the current glossary format which may not work in a popup.
             // for example "entry list" means the popup would only contain
             // a link that opens another popup.
-            $link = new url('/mod/glossary/showentry.php',
-                    ['eid' => $concept->id, 'displayformat' => 'dictionary']);
-            $attributes = array(
+            $link = new url(
+                '/mod/glossary/showentry.php',
+                ['eid' => $concept->id, 'displayformat' => 'dictionary']
+            );
+            $attributes = [
                     'href'  => $link,
                     'title' => str_replace('&amp;', '&', $title), // Undo the s() mangling.
                     'class' => 'glossary autolink concept glossaryid' . $concept->glossaryid,
                     'data-entryid' => $concept->id,
-                );
+                ];
         }
 
         // This flag is optionally set by resource_pluginfile()
@@ -156,7 +176,7 @@ class text_filter extends \core_filters\text_filter {
     }
 
     #[\Override]
-    public function filter($text, array $options = array()) {
+    public function filter($text, array $options = []) {
         global $GLOSSARY_EXCLUDEENTRY;
 
         $conceptlist = $this->get_all_concepts();
diff --git a/filter/mathjaxloader/classes/text_filter.php b/filter/mathjaxloader/classes/text_filter.php
index 07258e5f454..8578fb4364f 100644
--- a/filter/mathjaxloader/classes/text_filter.php
+++ b/filter/mathjaxloader/classes/text_filter.php
@@ -26,7 +26,7 @@ use core\url;
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class text_filter extends \core_filters\text_filter {
-    /*
+    /**
      * Perform a mapping of the moodle language code to the equivalent for MathJax.
      *
      * @param string $moodlelangcode - The moodle language code - e.g. en_pirate
@@ -38,7 +38,7 @@ class text_filter extends \core_filters\text_filter {
         $mathjaxlangcodes = [
             'ar', 'ast', 'bcc', 'bg', 'br', 'ca', 'cdo', 'ce', 'cs', 'cy', 'da', 'de', 'diq', 'en', 'eo', 'es', 'fa',
             'fi', 'fr', 'gl', 'he', 'ia', 'it', 'ja', 'kn', 'ko', 'lb', 'lki', 'lt', 'mk', 'nl', 'oc', 'pl', 'pt',
-            'pt-br', 'qqq', 'ru', 'scn', 'sco', 'sk', 'sl', 'sv', 'th', 'tr', 'uk', 'vi', 'zh-hans', 'zh-hant'
+            'pt-br', 'qqq', 'ru', 'scn', 'sco', 'sk', 'sl', 'sv', 'th', 'tr', 'uk', 'vi', 'zh-hans', 'zh-hant',
         ];
 
         // List of explicit mappings and known exceptions (moodle => mathjax).
@@ -69,39 +69,29 @@ class text_filter extends \core_filters\text_filter {
         return 'en';
     }
 
-    /*
-     * Add the javascript to enable mathjax processing on this page.
-     *
-     * @param moodle_page $page The current page.
-     * @param context $context The current context.
-     */
+    #[\Override]
     public function setup($page, $context) {
-
-        if ($page->requires->should_create_one_time_item_now('filter_mathjaxloader-scripts')) {
-            $url = get_config('filter_mathjaxloader', 'httpsurl');
-            $lang = $this->map_language_code(current_language());
-            $url = new url($url, array('delayStartupUntil' => 'configured'));
-
-            $page->requires->js($url);
-
-            $config = get_config('filter_mathjaxloader', 'mathjaxconfig');
-            $wwwroot = new url('/');
-
-            $config = str_replace('{wwwroot}', $wwwroot->out(true), $config);
-
-            $params = array('mathjaxconfig' => $config, 'lang' => $lang);
-
-            $page->requires->js_call_amd('filter_mathjaxloader/loader', 'configure', [$params]);
+        if (!$page->requires->should_create_one_time_item_now('filter_mathjaxloader-scripts')) {
+            return;
         }
+        $url = get_config('filter_mathjaxloader', 'httpsurl');
+        $lang = $this->map_language_code(current_language());
+        $url = new url($url, ['delayStartupUntil' => 'configured']);
+
+        $page->requires->js($url);
+
+        $config = get_config('filter_mathjaxloader', 'mathjaxconfig');
+        $wwwroot = new url('/');
+
+        $config = str_replace('{wwwroot}', $wwwroot->out(true), $config);
+
+        $params = ['mathjaxconfig' => $config, 'lang' => $lang];
+
+        $page->requires->js_call_amd('filter_mathjaxloader/loader', 'configure', [$params]);
     }
 
-    /*
-     * This function wraps the filtered text in a span, that mathjaxloader is configured to process.
-     *
-     * @param string $text The text to filter.
-     * @param array $options The filter options.
-     */
-    public function filter($text, array $options = array()) {
+    #[\Override]
+    public function filter($text, array $options = []) {
         global $PAGE;
 
         $legacy = get_config('filter_mathjaxloader', 'texfiltercompatibility');
@@ -148,7 +138,7 @@ class text_filter extends \core_filters\text_filter {
             // inside display math, only the outer display math is wrapped in
             // a span. The span HTML inside a LaTex math environment would break
             // MathJax. See MDL-61981.
-            list($text, $hasdisplayorinline) = $this->wrap_math_in_nolink($text);
+            [$text, $hasdisplayorinline] = $this->wrap_math_in_nolink($text);
         }
 
         if ($hasdisplayorinline || $hasextra) {
@@ -205,8 +195,10 @@ class text_filter extends \core_filters\text_filter {
                 }
             } else {
                 // Display math open.
-                if (($text[$i - 1] === '\\' && $text[$i] === ']' && $displaybracket) ||
-                        ($text[$i - 1] === '$' && $text[$i] === '$' && $displaydollar)) {
+                if (
+                    ($text[$i - 1] === '\\' && $text[$i] === ']' && $displaybracket) ||
+                        ($text[$i - 1] === '$' && $text[$i] === '$' && $displaydollar)
+                ) {
                     // Display math ends, wrap the span around it.
                     $text = $this->insert_span($text, $displaystart, $i);
 
@@ -221,7 +213,7 @@ class text_filter extends \core_filters\text_filter {
 
             ++$i;
         }
-        return array($text, $changesdone);
+        return [$text, $changesdone];
     }
 
     /**
@@ -237,10 +229,12 @@ class text_filter extends \core_filters\text_filter {
      * the defined substring.
      */
     protected function insert_span($text, $start, $end) {
-        return substr_replace($text,
-                '<span class="nolink">'. substr($text, $start, $end - $start + 1) .'</span>',
-                $start,
-                $end - $start + 1);
+        return substr_replace(
+            $text,
+            '<span class="nolink">' . substr($text, $start, $end - $start + 1) . '</span>',
+            $start,
+            $end - $start + 1
+        );
     }
 
     /**
@@ -252,7 +246,7 @@ class text_filter extends \core_filters\text_filter {
      * @return string Returns the input string with HTML tags escaped.
      */
     private function escape_html_tag_wrapper(string $text): string {
-        return preg_replace_callback('/\{([^}]+)\}/', function(array $matches): string {
+        return preg_replace_callback('/\{([^}]+)\}/', function (array $matches): string {
             $search = ['<', '>'];
             $replace = ['&lt;', '&gt;'];
             return str_replace($search, $replace, $matches[0]);
diff --git a/filter/mathjaxloader/tests/filtermath_test.php b/filter/mathjaxloader/tests/filtermath_test.php
index e66ef163291..3f918d23fe4 100644
--- a/filter/mathjaxloader/tests/filtermath_test.php
+++ b/filter/mathjaxloader/tests/filtermath_test.php
@@ -25,14 +25,14 @@ use core\context\system as context_system;
  * @category  test
  * @copyright 2018 Markku Riekkinen
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @covers \filter_mathjaxloader\text_filter
  */
 final class filtermath_test extends \advanced_testcase {
     /**
-     * Test the functionality of {@link text_filter::filter()}.
+     * Test the functionality of {@see text_filter::filter()}.
      *
      * @param string $inputtext The text given by the user.
      * @param string $expected The expected output after filtering.
-     *
      * @dataProvider math_filtering_inputs
      */
     public function test_math_filtering($inputtext, $expected): void {
@@ -45,53 +45,70 @@ final class filtermath_test extends \advanced_testcase {
      *
      * @return array of [inputtext, expectedoutput] tuples.
      */
-    public static function math_filtering_inputs() {
+    public static function math_filtering_inputs(): array {
+        // phpcs:disable moodle.Files.LineLength.TooLong
         return [
             // One inline formula.
-            ['Some inline math \\( y = x^2 \\).',
-            '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>', ],
+            [
+                'Some inline math \\( y = x^2 \\).',
+                '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>',
+            ],
 
             // One inline and one display.
-            ['Some inline math \\( y = x^2 \\) and display formula \\[ S = \\sum_{n=1}^{\\infty} 2^n \\]',
-            '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span> and '
-                . 'display formula <span class="nolink">\\[ S = \\sum_{n=1}^{\\infty} 2^n \\]</span></span>', ],
+            [
+                'Some inline math \\( y = x^2 \\) and display formula \\[ S = \\sum_{n=1}^{\\infty} 2^n \\]',
+                '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span> and '
+                    . 'display formula <span class="nolink">\\[ S = \\sum_{n=1}^{\\infty} 2^n \\]</span></span>',
+            ],
 
             // One display and one inline.
-            ['Display formula \\[ S = \\sum_{n=1}^{\\infty} 2^n \\] and some inline math \\( y = x^2 \\).',
-            '<span class="filter_mathjaxloader_equation">Display formula <span class="nolink">\\[ S = \\sum_{n=1}^{\\infty} 2^n \\]</span> and '
-                . 'some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>', ],
+            [
+                'Display formula \\[ S = \\sum_{n=1}^{\\infty} 2^n \\] and some inline math \\( y = x^2 \\).',
+                '<span class="filter_mathjaxloader_equation">Display formula <span class="nolink">\\[ S = \\sum_{n=1}^{\\infty} 2^n \\]</span> and '
+                    . 'some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>',
+            ],
 
             // One inline and one display (with dollars).
-            ['Some inline math \\( y = x^2 \\) and display formula $$ S = \\sum_{n=1}^{\\infty} 2^n $$',
-            '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span> and '
-                . 'display formula <span class="nolink">$$ S = \\sum_{n=1}^{\\infty} 2^n $$</span></span>', ],
+            [
+                'Some inline math \\( y = x^2 \\) and display formula $$ S = \\sum_{n=1}^{\\infty} 2^n $$',
+                '<span class="filter_mathjaxloader_equation">Some inline math <span class="nolink">\\( y = x^2 \\)</span> and '
+                    . 'display formula <span class="nolink">$$ S = \\sum_{n=1}^{\\infty} 2^n $$</span></span>',
+            ],
 
             // One display (with dollars) and one inline.
-            ['Display formula $$ S = \\sum_{n=1}^{\\infty} 2^n $$ and some inline math \\( y = x^2 \\).',
-            '<span class="filter_mathjaxloader_equation">Display formula <span class="nolink">$$ S = \\sum_{n=1}^{\\infty} 2^n $$</span> and '
-                . 'some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>', ],
+            [
+                'Display formula $$ S = \\sum_{n=1}^{\\infty} 2^n $$ and some inline math \\( y = x^2 \\).',
+                '<span class="filter_mathjaxloader_equation">Display formula <span class="nolink">$$ S = \\sum_{n=1}^{\\infty} 2^n $$</span> and '
+                    . 'some inline math <span class="nolink">\\( y = x^2 \\)</span>.</span>',
+            ],
 
             // Inline math environment nested inside display environment (using a custom LaTex macro).
-            ['\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\] '
-                . 'Text with inline formula using the custom LaTex macro \\( a = \\NullF \\).',
-            '<span class="filter_mathjaxloader_equation"><span class="nolink">'
-                . '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\]</span> '
-                . 'Text with inline formula using the custom LaTex macro <span class="nolink">\\( a = \\NullF \\)</span>.</span>', ],
+            [
+                '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\] '
+                    . 'Text with inline formula using the custom LaTex macro \\( a = \\NullF \\).',
+                '<span class="filter_mathjaxloader_equation"><span class="nolink">'
+                    . '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\]</span> '
+                    . 'Text with inline formula using the custom LaTex macro <span class="nolink">\\( a = \\NullF \\)</span>.</span>',
+            ],
 
             // Nested environments and some more content.
-            ['\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\] '
-                . 'Text with inline formula using the custom LaTex macro \\( a = \\NullF \\). Finally, a display formula '
-                . '$$ b = \\NullF $$',
-            '<span class="filter_mathjaxloader_equation"><span class="nolink">'
-                . '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\]</span> '
-                . 'Text with inline formula using the custom LaTex macro <span class="nolink">\\( a = \\NullF \\)</span>. '
-                . 'Finally, a display formula <span class="nolink">$$ b = \\NullF $$</span></span>', ],
+            [
+                '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\] '
+                    . 'Text with inline formula using the custom LaTex macro \\( a = \\NullF \\). Finally, a display formula '
+                    . '$$ b = \\NullF $$',
+                '<span class="filter_mathjaxloader_equation"><span class="nolink">'
+                    . '\\[ \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} \\]</span> '
+                    . 'Text with inline formula using the custom LaTex macro <span class="nolink">\\( a = \\NullF \\)</span>. '
+                    . 'Finally, a display formula <span class="nolink">$$ b = \\NullF $$</span></span>',
+            ],
 
             // Broken math: the delimiters ($$) are not closed.
-            ['Writing text and starting display math. $$ k = i^3 \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} '
-                . 'More text and inline math \\( x = \\NullF \\).',
-            'Writing text and starting display math. $$ k = i^3 \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} '
-                . 'More text and inline math \\( x = \\NullF \\).', ],
+            [
+                'Writing text and starting display math. $$ k = i^3 \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} '
+                    . 'More text and inline math \\( x = \\NullF \\).',
+                'Writing text and starting display math. $$ k = i^3 \\newcommand{\\False}{\\mathsf{F}} \\newcommand{\\NullF}{\\fbox{\\(\\False\\)}} '
+                    . 'More text and inline math \\( x = \\NullF \\).',
+            ],
         ];
     }
 }
diff --git a/filter/mathjaxloader/tests/text_filter_test.php b/filter/mathjaxloader/tests/text_filter_test.php
index e5474b1ac5f..891b2aed4dd 100644
--- a/filter/mathjaxloader/tests/text_filter_test.php
+++ b/filter/mathjaxloader/tests/text_filter_test.php
@@ -27,11 +27,10 @@ namespace filter_mathjaxloader;
  */
 final class text_filter_test extends \advanced_testcase {
     /**
-     * Test the functionality of {@link text_filter::map_language_code()}.
+     * Test the functionality of {@see text_filter::map_language_code()}.
      *
      * @param string $moodlelangcode the user's current language
      * @param string $mathjaxlangcode the mathjax language to be used for the moodle language
-     *
      * @dataProvider map_language_code_expected_mappings
      */
     public function test_map_language_code($moodlelangcode, $mathjaxlangcode): void {
@@ -44,7 +43,7 @@ final class text_filter_test extends \advanced_testcase {
      *
      * @return array of [moodlelangcode, mathjaxcode] tuples
      */
-    public static function map_language_code_expected_mappings() {
+    public static function map_language_code_expected_mappings(): array {
         return [
             ['cz', 'cs'], // Explicit mapping.
             ['cs', 'cs'], // Implicit mapping (exact match).
diff --git a/filter/mediaplugin/classes/text_filter.php b/filter/mediaplugin/classes/text_filter.php
index ed814c8d9e7..339cb180512 100644
--- a/filter/mediaplugin/classes/text_filter.php
+++ b/filter/mediaplugin/classes/text_filter.php
@@ -28,7 +28,7 @@ use moodle_page;
  * It is highly recommended to configure servers to be compatible with our slasharguments,
  * otherwise the "?d=600x400" may not work.
  *
- * @package    filter
+ * @package    filter_mediaplugin
  * @subpackage mediaplugin
  * @copyright  2004 onwards Martin Dougiamas  {@link http://moodle.com}
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -56,11 +56,11 @@ class text_filter extends \core_filters\text_filter {
     }
 
     #[\Override]
-    public function filter($text, array $options = array()) {
+    public function filter($text, array $options = []) {
         global $CFG, $PAGE;
 
-        if (!is_string($text) or empty($text)) {
-            // non string data can not be filtered anyway
+        if (!is_string($text) || empty($text)) {
+            // Non string data can not be filtered anyway.
             return $text;
         }
 
@@ -70,7 +70,7 @@ class text_filter extends \core_filters\text_filter {
         }
 
         // Check permissions.
-        $this->trusted = !empty($options['noclean']) or !empty($CFG->allowobjectembed);
+        $this->trusted = !empty($options['noclean']) || !empty($CFG->allowobjectembed);
 
         // Looking for tags.
         $matches = preg_split('/(<[^>]*>)/i', $text, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
@@ -92,14 +92,14 @@ class text_filter extends \core_filters\text_filter {
         // and build them so that the callback function can check it for
         // embedded content. Then we rebuild the string.
         foreach ($matches as $idx => $tag) {
-            if (preg_match('|</'.$tagname.'>|', $tag) && !empty($validtag)) {
+            if (preg_match('|</' . $tagname . '>|', $tag) && !empty($validtag)) {
                 $validtag .= $tag;
 
                 // Given we now have a valid <a> tag to process it's time for
                 // ReDoS protection. Stop processing if a word is too large.
                 if (strlen($validtag) < 4096) {
                     if ($tagname === 'a') {
-                        $processed = preg_replace_callback($re, array($this, 'callback'), $validtag);
+                        $processed = preg_replace_callback($re, [$this, 'callback'], $validtag);
                     } else {
                         // For audio and video tags we just process them without precheck for embeddable markers.
                         $processed = $this->process_media_tag($validtag);
@@ -110,8 +110,10 @@ class text_filter extends \core_filters\text_filter {
                 // Wipe it so we can catch any more instances to filter.
                 $validtag = '';
                 $processed = '';
-            } else if (preg_match('/<(a|video|audio)\s[^>]*/', $tag, $tagmatches) && $sizeofmatches > 1 &&
-                    (empty($validtag) || $tagname === strtolower($tagmatches[1]))) {
+            } else if (
+                preg_match('/<(a|video|audio)\s[^>]*/', $tag, $tagmatches) && $sizeofmatches > 1 &&
+                    (empty($validtag) || $tagname === strtolower($tagmatches[1]))
+            ) {
                 // Looking for a starting tag. Ignore tags embedded into each other.
                 $validtag = $tag;
                 $tagname = strtolower($tagmatches[1]);
@@ -147,7 +149,7 @@ class text_filter extends \core_filters\text_filter {
 
         // Get name.
         $name = trim($matches[2]);
-        if (empty($name) or strpos($name, 'http') === 0) {
+        if (empty($name) || strpos($name, 'http') === 0) {
             $name = ''; // Use default name.
         }
 
diff --git a/filter/mediaplugin/dev/perftest.php b/filter/mediaplugin/dev/perftest.php
index d51ac061fc7..a14a25bae33 100644
--- a/filter/mediaplugin/dev/perftest.php
+++ b/filter/mediaplugin/dev/perftest.php
@@ -44,7 +44,7 @@ $enabledmediaplugins = \core\plugininfo\media::get_enabled_plugins();
 \core\plugininfo\media::set_enabled_plugins('vimeo,youtube,videojs,html5audio,html5video');
 
 // Create plugin.
-$filterplugin = new \filter_mediaplugin\text_filter(null, array());
+$filterplugin = new \filter_mediaplugin\text_filter(null, []);
 
 // Note: As this is a developer test page, language strings are not used: all
 // text is English-only.
diff --git a/filter/multilang/classes/text_filter.php b/filter/multilang/classes/text_filter.php
index d9564ea6312..9d63b171934 100644
--- a/filter/multilang/classes/text_filter.php
+++ b/filter/multilang/classes/text_filter.php
@@ -40,30 +40,27 @@ namespace filter_multilang;
  */
 class text_filter extends \core_filters\text_filter {
     #[\Override]
-    public function filter($text, array $options = array()) {
+    public function filter($text, array $options = []) {
         global $CFG;
 
-        // [pj] I don't know about you but I find this new implementation funny :P
-        // [skodak] I was laughing while rewriting it ;-)
-        // [nicolasconnault] Should support inverted attributes: <span class="multilang" lang="en"> (Doesn't work curently)
-        // [skodak] it supports it now, though it is slower - any better idea?
-
-        if (empty($text) or is_numeric($text)) {
+        if (empty($text) || is_numeric($text)) {
             return $text;
         }
 
-        if (empty($CFG->filter_multilang_force_old) and !empty($CFG->filter_multilang_converted)) {
-            // new syntax
+        if (empty($CFG->filter_multilang_force_old) && !empty($CFG->filter_multilang_converted)) {
+            // New syntax.
+            // phpcs:ignore moodle.Files.LineLength.TooLong
             $search = '/(<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)(\s*<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)+/is';
         } else {
-            // old syntax
+            // Old syntax.
+            // phpcs:ignore moodle.Files.LineLength.TooLong
             $search = '/(<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)(\s*<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)+/is';
         }
 
         $result = preg_replace_callback($search, [$this, 'process_match'], $text);
 
         if (is_null($result)) {
-            return $text; //error during regex processing (too many nested spans?)
+            return $text; // Error during regex processing (too many nested spans?).
         } else {
             return $result;
         }
@@ -83,7 +80,7 @@ class text_filter extends \core_filters\text_filter {
             return $langblock[0];
         }
 
-        $langlist = array();
+        $langlist = [];
         foreach ($rawlanglist[1] as $index => $lang) {
             $lang = str_replace('-', '_', strtolower($lang)); // Normalize languages.
             $langlist[$lang] = $rawlanglist[2][$index];
diff --git a/filter/tests/external/get_available_in_context_test.php b/filter/tests/external/get_available_in_context_test.php
index 95792d10b5c..1f3dfad08c0 100644
--- a/filter/tests/external/get_available_in_context_test.php
+++ b/filter/tests/external/get_available_in_context_test.php
@@ -56,7 +56,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
         $this->setAdminUser();
 
         $this->expectException('moodle_exception');
-        get_available_in_context::execute(array(array('contextlevel' => 'system', 'instanceid' => 0)));
+        get_available_in_context::execute([['contextlevel' => 'system', 'instanceid' => 0]]);
     }
 
     /**
@@ -76,7 +76,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
             filter_set_global_state($filter, TEXTFILTER_DISABLED);
         }
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'coursecat', 'instanceid' => $category->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'coursecat', 'instanceid' => $category->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['filters']); // No filters, all disabled.
         $this->assertEmpty($result['warnings']);
@@ -86,7 +86,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
         $firstfilter = key($allfilters);
         filter_set_global_state($firstfilter, TEXTFILTER_ON);
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'coursecat', 'instanceid' => $category->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'coursecat', 'instanceid' => $category->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled.
@@ -95,7 +95,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
 
         // Set off the same filter at local context level.
         filter_set_local_state($firstfilter, \context_coursecat::instance($category->id)->id, TEXTFILTER_OFF);
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'coursecat', 'instanceid' => $category->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'coursecat', 'instanceid' => $category->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled globally.
@@ -120,7 +120,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
             filter_set_global_state($filter, TEXTFILTER_DISABLED);
         }
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'course', 'instanceid' => $course->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'course', 'instanceid' => $course->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['filters']); // No filters, all disabled at global level.
         $this->assertEmpty($result['warnings']);
@@ -130,7 +130,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
         $firstfilter = key($allfilters);
         filter_set_global_state($firstfilter, TEXTFILTER_ON);
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'course', 'instanceid' => $course->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'course', 'instanceid' => $course->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled.
@@ -139,7 +139,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
 
         // Set off the same filter at local context level.
         filter_set_local_state($firstfilter, \context_course::instance($course->id)->id, TEXTFILTER_OFF);
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'course', 'instanceid' => $course->id)));
+        $result = get_available_in_context::execute([['contextlevel' => 'course', 'instanceid' => $course->id]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled globally.
@@ -158,7 +158,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
 
         // Create one activity.
         $course = self::getDataGenerator()->create_course();
-        $forum = self::getDataGenerator()->create_module('forum', (object) array('course' => $course->id));
+        $forum = self::getDataGenerator()->create_module('forum', (object) ['course' => $course->id]);
 
         // Get all filters and disable them all globally.
         $allfilters = filter_get_all_installed();
@@ -166,7 +166,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
             filter_set_global_state($filter, TEXTFILTER_DISABLED);
         }
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'module', 'instanceid' => $forum->cmid)));
+        $result = get_available_in_context::execute([['contextlevel' => 'module', 'instanceid' => $forum->cmid]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['filters']); // No filters, all disabled at global level.
         $this->assertEmpty($result['warnings']);
@@ -176,7 +176,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
         $firstfilter = key($allfilters);
         filter_set_global_state($firstfilter, TEXTFILTER_ON);
 
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'module', 'instanceid' => $forum->cmid)));
+        $result = get_available_in_context::execute([['contextlevel' => 'module', 'instanceid' => $forum->cmid]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled.
@@ -185,7 +185,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
 
         // Set off the same filter at local context level.
         filter_set_local_state($firstfilter, \context_module::instance($forum->cmid)->id, TEXTFILTER_OFF);
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'module', 'instanceid' => $forum->cmid)));
+        $result = get_available_in_context::execute([['contextlevel' => 'module', 'instanceid' => $forum->cmid]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertEmpty($result['warnings']);
         $this->assertEquals($firstfilter, $result['filters'][0]['filter']); // OK, the filter is enabled globally.
@@ -195,7 +195,7 @@ final class get_available_in_context_test extends externallib_advanced_testcase
         // Try user without permission, warning expected.
         $user = $this->getDataGenerator()->create_user();
         $this->setUser($user);
-        $result = get_available_in_context::execute(array(array('contextlevel' => 'module', 'instanceid' => $forum->cmid)));
+        $result = get_available_in_context::execute([['contextlevel' => 'module', 'instanceid' => $forum->cmid]]);
         $result = external_api::clean_returnvalue(get_available_in_context::execute_returns(), $result);
         $this->assertNotEmpty($result['warnings']);
         $this->assertEquals('context', $result['warnings'][0]['item']);
diff --git a/filter/tex/classes/text_filter.php b/filter/tex/classes/text_filter.php
index ea35f867795..ff58dc5dd7d 100644
--- a/filter/tex/classes/text_filter.php
+++ b/filter/tex/classes/text_filter.php
@@ -34,7 +34,7 @@ use stdClass;
  * Note that there may be patent restrictions on the production of gif images
  * in Canada and some parts of Western Europe and Japan until July 2004.
  *
- * @package    filter
+ * @package    filter_tex
  * @subpackage tex
  * @copyright  2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
  *             Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
@@ -45,73 +45,60 @@ class text_filter extends \core_filters\text_filter {
     public function filter($text, array $options = []) {
         global $CFG, $DB;
 
-        /// Do a quick check using stripos to avoid unnecessary work
-        if ((!preg_match('/<tex/i', $text)) &&
-                (strpos($text,'$$') === false) &&
-                (strpos($text,'\\[') === false) &&
+        // Do a quick check using stripos to avoid unnecessary work.
+        if (
+            (!preg_match('/<tex/i', $text)) &&
+                (strpos($text, '$$') === false) &&
+                (strpos($text, '\\[') === false) &&
                 (strpos($text, '\\(') === false) &&
-                (!preg_match('/\[tex/i',$text))) {
+                (!preg_match('/\[tex/i', $text))
+        ) {
             return $text;
         }
 
-#    //restrict filtering to forum 130 (Maths Tools on moodle.org)
-#    $scriptname = $_SERVER['SCRIPT_NAME'];
-#    if (!strstr($scriptname,'/forum/')) {
-#        return $text;
-#    }
-#    if (strstr($scriptname,'post.php')) {
-#        $parent = forum_get_post_full($_GET['reply']);
-#        $discussion = $DB->get_record("forum_discussions", array("id"=>$parent->discussion));
-#    } else if (strstr($scriptname,'discuss.php')) {
-#        $discussion = $DB->get_record("forum_discussions", array("id"=>$_GET['d']));
-#    } else {
-#        return $text;
-#    }
-#    if ($discussion->forum != 130) {
-#        return $text;
-#    }
         $text .= ' ';
-        preg_match_all('/\$(\$\$+?)([^\$])/s',$text,$matches);
-        for ($i=0; $i<count($matches[0]); $i++) {
-            $replacement = str_replace('$','&#x00024;', $matches[1][$i]).$matches[2][$i];
+        preg_match_all('/\$(\$\$+?)([^\$])/s', $text, $matches);
+        for ($i = 0; $i < count($matches[0]); $i++) {
+            $replacement = str_replace('$', '&#x00024;', $matches[1][$i]) . $matches[2][$i];
             $text = str_replace($matches[0][$i], $replacement, $text);
         }
 
+        // The following regular expression matches TeX expressions delimited by:
         // <tex> TeX expression </tex>
         // or <tex alt="My alternative text to be used instead of the TeX form"> TeX expression </tex>
         // or $$ TeX expression $$
-        // or \[ TeX expression \]          // original tag of MathType and TeXaide (dlnsk)
-        // or [tex] TeX expression [/tex]   // somtime it's more comfortable than <tex> (dlnsk)
-        $rules = array(
+        // or \[ TeX expression \]          // original tag of MathType and TeXaide
+        // or [tex] TeX expression [/tex]   // somtime it's more comfortable than <tex>.
+        $rules = [
             '<tex(?:\s+alt=["\'](.*?)["\'])?>(.+?)<\/tex>',
             '\$\$(.+?)\$\$',
             '\\\\\[(.+?)\\\\\]',
             '\\\\\((.+?)\\\\\)',
-            '\\[tex\\](.+?)\\[\/tex\\]'
-        );
+            '\\[tex\\](.+?)\\[\/tex\\]',
+        ];
         $megarule = '/' . implode('|', $rules) . '/is';
         preg_match_all($megarule, $text, $matches);
-        for ($i=0; $i<count($matches[0]); $i++) {
+        for ($i = 0; $i < count($matches[0]); $i++) {
             $texexp = '';
             for ($j = 0; $j < count($rules); $j++) {
                 $texexp .= $matches[$j + 2][$i];
             }
             $alt = $matches[1][$i];
-            $texexp = str_replace('<nolink>','',$texexp);
-            $texexp = str_replace('</nolink>','',$texexp);
-            $texexp = str_replace('<span class="nolink">','',$texexp);
-            $texexp = str_replace('</span>','',$texexp);
-            $texexp = preg_replace("/<br[[:space:]]*\/?>/i", '', $texexp);  //dlnsk
+            $texexp = str_replace('<nolink>', '', $texexp);
+            $texexp = str_replace('</nolink>', '', $texexp);
+            $texexp = str_replace('<span class="nolink">', '', $texexp);
+            $texexp = str_replace('</span>', '', $texexp);
+            $texexp = preg_replace("/<br[[:space:]]*\/?>/i", '', $texexp);
             $align = "middle";
-            if (preg_match('/^align=bottom /',$texexp)) {
-              $align = "text-bottom";
-              $texexp = preg_replace('/^align=bottom /','',$texexp);
-            } else if (preg_match('/^align=top /',$texexp)) {
-              $align = "text-top";
-              $texexp = preg_replace('/^align=top /','',$texexp);
+            if (preg_match('/^align=bottom /', $texexp)) {
+                $align = "text-bottom";
+                $texexp = preg_replace('/^align=bottom /', '', $texexp);
+            } else if (preg_match('/^align=top /', $texexp)) {
+                $align = "text-top";
+                $texexp = preg_replace('/^align=top /', '', $texexp);
             }
 
-            // decode entities encoded by editor, luckily there is very little chance of double decoding
+            // Decode entities encoded by editor, luckily there is very little chance of double decoding.
             $texexp = html_entity_decode($texexp, ENT_QUOTES, 'UTF-8');
 
             if ($texexp === '') {
@@ -122,7 +109,7 @@ class text_filter extends \core_filters\text_filter {
             $texexp = clean_param($texexp, PARAM_TEXT);
 
             $md5 = md5($texexp);
-            if (!$DB->record_exists("cache_filters", array("filter"=>"tex", "md5key"=>$md5))) {
+            if (!$DB->record_exists("cache_filters", ["filter" => "tex", "md5key" => $md5])) {
                 $texcache = new stdClass();
                 $texcache->filter = 'tex';
                 $texcache->version = 1;
@@ -135,8 +122,8 @@ class text_filter extends \core_filters\text_filter {
             if ($convertformat == 'svg' && !core_useragent::supports_svg()) {
                 $convertformat = 'png';
             }
-            $filename = $md5.".{$convertformat}";
-            $text = str_replace( $matches[0][$i], self::get_image_markup($filename, $texexp, 0, 0, $align, $alt), $text);
+            $filename = $md5 . ".{$convertformat}";
+            $text = str_replace($matches[0][$i], $this->get_image_markup($filename, $texexp, 0, 0, $align, $alt), $text);
         }
         return $text;
     }
@@ -163,11 +150,11 @@ class text_filter extends \core_filters\text_filter {
         global $CFG, $OUTPUT;
 
         if (!$imagefile) {
-            throw new coding_exception('image file argument empty in get_image_markup()');
+            throw new coding_exception('Image file argument empty in get_image_markup()');
         }
 
         // Work out any necessary inline style.
-        $rules = array();
+        $rules = [];
         if ($align !== 'middle') {
             $rules[] = 'vertical-align:' . $align . ';';
         }
@@ -189,7 +176,7 @@ class text_filter extends \core_filters\text_filter {
         // users (to provide a text equivalent to the equation) while the title
         // is there as a convenience for sighted users who want to see the TeX
         // code.
-        $title = 'title="'.s($tex).'"';
+        $title = 'title="' . s($tex) . '"';
 
         if ($alt === '') {
             $alt = s($tex);
@@ -199,21 +186,24 @@ class text_filter extends \core_filters\text_filter {
 
         // Build the output.
         $anchorcontents = "<img class=\"texrender\" $title alt=\"$alt\" src=\"";
-        if ($CFG->slasharguments) {        // Use this method if possible for better caching
+        if ($CFG->slasharguments) {
+            // Use this method if possible for better client-side caching.
             $anchorcontents .= "$CFG->wwwroot/filter/tex/pix.php/$imagefile";
         } else {
             $anchorcontents .= "$CFG->wwwroot/filter/tex/pix.php?file=$imagefile";
         }
         $anchorcontents .= "\" $style/>";
 
-        if (!file_exists("$CFG->dataroot/filter/tex/$imagefile") && has_capability('moodle/site:config', context_system::instance())) {
+        $imagefound = file_exists("$CFG->dataroot/filter/tex/$imagefile");
+        if (!$imagefound && has_capability('moodle/site:config', context_system::instance())) {
             $link = '/filter/tex/texdebug.php';
             $action = null;
         } else {
-            $link = new url('/filter/tex/displaytex.php', array('texexp'=>$tex));
-            $action = new popup_action('click', $link, 'popup', array('width'=>320,'height'=>240));
+            $link = new url('/filter/tex/displaytex.php', ['texexp' => $tex]);
+            $action = new popup_action('click', $link, 'popup', ['width' => 320, 'height' => 240]);
         }
-        $output = $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX')); //TODO: the popups do not work when text caching is enabled!!
+        // TODO: the popups do not work when text caching is enabled.
+        $output = $OUTPUT->action_link($link, $anchorcontents, $action, ['title' => 'TeX']);
         $output = "<span class=\"MathJax_Preview\">$output</span><script type=\"math/tex\">$tex</script>";
 
         return $output;
diff --git a/filter/tex/tests/text_filter_test.php b/filter/tex/tests/text_filter_test.php
index 5efcf584965..837cd03bb23 100644
--- a/filter/tex/tests/text_filter_test.php
+++ b/filter/tex/tests/text_filter_test.php
@@ -81,7 +81,7 @@ final class text_filter_test extends \advanced_testcase {
             ['$', '$', false],
             ['(', ')', false],
             ['[', ']', false],
-            ['$$', '\\]', false]
+            ['$$', '\\]', false],
         ];
     }
 }
diff --git a/filter/tidy/classes/text_filter.php b/filter/tidy/classes/text_filter.php
index bfe2b95da9c..93ac723d15d 100644
--- a/filter/tidy/classes/text_filter.php
+++ b/filter/tidy/classes/text_filter.php
@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
+namespace filter_tidy;
+
 /**
  * HTML tidy text filter.
  *
@@ -36,8 +38,8 @@
 class text_filter extends \core_filters\text_filter {
     #[\Override]
     public function filter($text, array $options = []) {
-        // Configuration for tidy. Feel free to tune for your needs, e.g. to allow
-        // proprietary markup.
+        // Configuration for tidy.
+        // See https://api.html-tidy.org/tidy/quickref_5.0.0.html for details.
         $tidyoptions = [
             'output-xhtml' => true,
             'show-body-only' => true,
@@ -53,12 +55,11 @@ class text_filter extends \core_filters\text_filter {
             return $text;
         }
 
-
         // If enabled: run tidy over the entire string.
-        if (function_exists('tidy_repair_string')) {
+        if (extension_loaded('tidy')) {
             $currentlocale = \core\locale::get_locale();
             try {
-                $text = tidy_repair_string($text, $tidyoptions, 'utf8');
+                $text = (new \tidy())->repairString($text, $tidyoptions, 'utf8');
             } finally {
                 \core\locale::set_locale(LC_ALL, $currentlocale);
             }
diff --git a/filter/urltolink/classes/text_filter.php b/filter/urltolink/classes/text_filter.php
index de18157e3a7..bc471ef0988 100644
--- a/filter/urltolink/classes/text_filter.php
+++ b/filter/urltolink/classes/text_filter.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -26,19 +25,19 @@ namespace filter_urltolink;
  */
 class text_filter extends \core_filters\text_filter {
     /**
-     * @var array global configuration for this filter
-     *
      * This might be eventually moved into parent class if we found it
      * useful for other filters, too.
+     *
+     * @var array global configuration for this filter
      */
     protected static $globalconfig;
 
     #[\Override]
-    public function filter($text, array $options = array()) {
+    public function filter($text, array $options = []) {
         if (!isset($options['originalformat'])) {
-            // if the format is not specified, we are probably called by {@see format_string()}
+            // If the format is not specified, we are probably called by {@see format_string()}
             // in that case, it would be dangerous to replace URL with the link because it could
-            // be stripped. therefore, we do nothing
+            // be stripped. therefore, we do nothing.
             return $text;
         }
         if (in_array($options['originalformat'], explode(',', get_config('filter_urltolink', 'formats')))) {
@@ -47,26 +46,22 @@ class text_filter extends \core_filters\text_filter {
         return $text;
     }
 
-    ////////////////////////////////////////////////////////////////////////////
-    // internal implementation starts here
-    ////////////////////////////////////////////////////////////////////////////
-
     /**
      * Given some text this function converts any URLs it finds into HTML links
      *
      * @param string $text Passed in by reference. The string to be searched for urls.
      */
     protected function convert_urls_into_links(&$text) {
-        //I've added img tags to this list of tags to ignore.
-        //See MDL-21168 for more info. A better way to ignore tags whether or not
-        //they are escaped partially or completely would be desirable. For example:
-        //<a href="blah">
-        //&lt;a href="blah"&gt;
-        //&lt;a href="blah">
-        $filterignoretagsopen  = array('<a\s[^>]+?>', '<span[^>]+?class="nolink"[^>]*?>');
-        $filterignoretagsclose = array('</a>', '</span>');
+        // I've added img tags to this list of tags to ignore.
+        // See MDL-21168 for more info. A better way to ignore tags whether or not
+        // they are escaped partially or completely would be desirable. For example:
+        // <a href="blah">
+        // &lt;a href="blah"&gt;
+        // &lt;a href="blah">.
+        $filterignoretagsopen  = ['<a\s[^>]+?>', '<span[^>]+?class="nolink"[^>]*?>'];
+        $filterignoretagsclose = ['</a>', '</span>'];
         $ignoretags = [];
-        filter_save_ignore_tags($text,$filterignoretagsopen,$filterignoretagsclose,$ignoretags);
+        filter_save_ignore_tags($text, $filterignoretagsopen, $filterignoretagsclose, $ignoretags);
 
         // Check if we support unicode modifiers in regular expressions. Cache it.
         // TODO: this check should be a environment requirement in Moodle 2.0, as far as unicode
@@ -76,10 +71,10 @@ class text_filter extends \core_filters\text_filter {
         // Unicode check, negative assertion and other bits from Moodle.
         static $unicoderegexp;
         if (!isset($unicoderegexp)) {
-            $unicoderegexp = @preg_match('/\pL/u', 'a'); // This will fail silently, returning false,
+            $unicoderegexp = @preg_match('/\pL/u', 'a'); // This will fail silently, returning false.
         }
 
-        // TODO MDL-21296 - use of unicode modifiers may cause a timeout
+        // TODO MDL-21296 - use of unicode modifiers may cause a timeout.
         $urlstart = '(?:http(s)?://|(?<!://)(www\.))';
         $domainsegment = '(?:[\pLl0-9][\pLl0-9-]*[\pLl0-9]|[\pLl0-9])';
         $numericip = '(?:(?:[0-9]{1,3}\.){3}[0-9]{1,3})';
@@ -98,7 +93,7 @@ class text_filter extends \core_filters\text_filter {
         if ($unicoderegexp) {
             $regex = '#' . $regex . '#ui';
         } else {
-            $regex = '#' . preg_replace(array('\pLl', '\PL'), 'a-z', $regex) . '#i';
+            $regex = '#' . preg_replace(['\pLl', '\PL'], 'a-z', $regex) . '#i';
         }
 
         // Locate any HTML tags.
@@ -135,14 +130,14 @@ class text_filter extends \core_filters\text_filter {
         $text = implode('', $matches);
 
         if (!empty($ignoretags)) {
-            $ignoretags = array_reverse($ignoretags); /// Reversed so "progressive" str_replace() will solve some nesting problems.
-            $text = str_replace(array_keys($ignoretags),$ignoretags,$text);
+            $ignoretags = array_reverse($ignoretags); // Reversed so "progressive" str_replace() will solve some nesting problems.
+            $text = str_replace(array_keys($ignoretags), $ignoretags, $text);
         }
 
         if (get_config('filter_urltolink', 'embedimages')) {
-            // now try to inject the images, this code was originally in the mediapluing filter
+            // Now try to inject the images, this code was originally in the mediapluing filter
             // this may be useful only if somebody relies on the fact the links in FORMAT_MOODLE get converted
-            // to URLs which in turn change to real images
+            // to URLs which in turn change to real images.
             $search = '/<a href="([^"]+\.(jpg|png|gif))" class="_blanktarget">([^>]*)<\/a>/is';
             $text = preg_replace_callback($search, [self::class, 'get_image_markup'], $text);
         }
@@ -153,14 +148,14 @@ class text_filter extends \core_filters\text_filter {
      *
      * This plugin is intended for automatic conversion of image URLs when FORMAT_MOODLE used.
      *
-     * @param  $link
+     * @param array $link
      * @return string
      */
     private function get_image_markup($link) {
         if ($link[1] !== $link[3]) {
-            // this is not a link created by this filter, because the url does not match the text
+            // This is not a link created by this filter, because the url does not match the text.
             return $link[0];
         }
-        return '<img class="filter_urltolink_image" alt="" src="'.$link[1].'" />';
+        return '<img class="filter_urltolink_image" alt="" src="' . $link[1] . '" />';
     }
 }
diff --git a/filter/urltolink/tests/text_filter_test.php b/filter/urltolink/tests/text_filter_test.php
index c8945606591..2583b20d511 100644
--- a/filter/urltolink/tests/text_filter_test.php
+++ b/filter/urltolink/tests/text_filter_test.php
@@ -26,11 +26,17 @@ namespace filter_urltolink;
  * @covers \filter_urltolink\text_filter
  */
 final class text_filter_test extends \basic_testcase {
+    /**
+     * Data provider for test_convert_urls_into_links.
+     *
+     * @return array
+     */
     public static function get_convert_urls_into_links_test_cases(): array {
         // Create a 4095 and 4096 long URLs.
         $superlong4095 = str_pad('http://www.superlong4095.com?this=something', 4095, 'a');
         $superlong4096 = str_pad('http://www.superlong4096.com?this=something', 4096, 'a');
 
+        // phpcs:disable moodle.Files.LineLength.MaxExceeded, moodle.Files.LineLength.TooLong
         $texts = [
             // Just a url.
             'http://moodle.org - URL' => '<a href="http://moodle.org" class="_blanktarget">http://moodle.org</a> - URL',
@@ -70,8 +76,6 @@ final class text_filter_test extends \basic_testcase {
             'URL: www.cc.org/url_(withpar)_go/?i=2' => 'URL: <a href="http://www.cc.org/url_(withpar)_go/?i=2" class="_blanktarget">www.cc.org/url_(withpar)_go/?i=2</a>',
             'URL: http://cc.org/url_(with)_(par)_go/?i=2' => 'URL: <a href="http://cc.org/url_(with)_(par)_go/?i=2" class="_blanktarget">http://cc.org/url_(with)_(par)_go/?i=2</a>',
             'URL: www.cc.org/url_(with)_(par)_go/?i=2' => 'URL: <a href="http://www.cc.org/url_(with)_(par)_go/?i=2" class="_blanktarget">www.cc.org/url_(with)_(par)_go/?i=2</a>',
-            // URL legitimately ending in a bracket. Commented out as part of MDL-22390. See next tests for work-arounds.
-            // 'http://en.wikipedia.org/wiki/Slash_(punctuation)'=>'<a href="http://en.wikipedia.org/wiki/Slash_(punctuation)" class="_blanktarget">http://en.wikipedia.org/wiki/Slash_(punctuation)</a>',
             'http://en.wikipedia.org/wiki/%28#Parentheses_.28_.29 - URL' => '<a href="http://en.wikipedia.org/wiki/%28#Parentheses_.28_.29" class="_blanktarget">http://en.wikipedia.org/wiki/%28#Parentheses_.28_.29</a> - URL',
             'http://en.wikipedia.org/wiki/(#Parentheses_.28_.29 - URL' => '<a href="http://en.wikipedia.org/wiki/(#Parentheses_.28_.29" class="_blanktarget">http://en.wikipedia.org/wiki/(#Parentheses_.28_.29</a> - URL',
             // Escaped brackets in url.
@@ -134,16 +138,14 @@ final class text_filter_test extends \basic_testcase {
             '<table style="background-image: url(http://moodle.org/pic.jpg);">' => '<table style="background-image: url(http://moodle.org/pic.jpg);">',
             '<table style="background-image: url("http://moodle.org/pic.jpg");">' => '<table style="background-image: url("http://moodle.org/pic.jpg");">',
             '<table style="background-image: url( http://moodle.org/pic.jpg );">' => '<table style="background-image: url( http://moodle.org/pic.jpg );">',
-            // Partially escaped img tag
+            // Partially escaped img tag.
             'partially escaped img tag &lt;img src="http://moodle.org/logo/logo-240x60.gif" />' => 'partially escaped img tag &lt;img src="http://moodle.org/logo/logo-240x60.gif" />',
-            // Fully escaped img tag. Commented out as part of MDL-21183
-            // Htmlspecialchars('fully escaped img tag <img src="http://moodle.org/logo/logo-240x60.gif" />') => 'fully escaped img tag &lt;img src="http://moodle.org/logo/logo-240x60.gif" /&gt;',
-            // Double http with www
+            // Double http with www.
             'One more link like http://www.moodle.org to test' => 'One more link like <a href="http://www.moodle.org" class="_blanktarget">http://www.moodle.org</a> to test',
-            // Encoded URLs in the path
+            // Encoded URLs in the path.
             'URL: http://127.0.0.1/one%28parenthesis%29/path?param=value' => 'URL: <a href="http://127.0.0.1/one%28parenthesis%29/path?param=value" class="_blanktarget">http://127.0.0.1/one%28parenthesis%29/path?param=value</a>',
             'URL: www.localhost.com/one%28parenthesis%29/path?param=value' => 'URL: <a href="http://www.localhost.com/one%28parenthesis%29/path?param=value" class="_blanktarget">www.localhost.com/one%28parenthesis%29/path?param=value</a>',
-            // Encoded URLs in the query
+            // Encoded URLs in the query.
             'URL: http://127.0.0.1/path/to?param=value_with%28parenthesis%29&param2=1' => 'URL: <a href="http://127.0.0.1/path/to?param=value_with%28parenthesis%29&param2=1" class="_blanktarget">http://127.0.0.1/path/to?param=value_with%28parenthesis%29&param2=1</a>',
             'URL: www.localhost.com/path/to?param=value_with%28parenthesis%29&param2=1' => 'URL: <a href="http://www.localhost.com/path/to?param=value_with%28parenthesis%29&param2=1" class="_blanktarget">www.localhost.com/path/to?param=value_with%28parenthesis%29&param2=1</a>',
             // Test URL less than 4096 characters in size is converted to link.
@@ -173,6 +175,8 @@ final class text_filter_test extends \basic_testcase {
             '<span class="nolink">URL: http://moodle.org</span>' => '<span class="nolink">URL: http://moodle.org</span>',
         ];
 
+        // phpcs:enable
+
         $data = [];
         foreach ($texts as $text => $correctresult) {
             $data[] = [$text, $correctresult];
@@ -181,7 +185,11 @@ final class text_filter_test extends \basic_testcase {
     }
 
     /**
+     * Test the convert_urls_into_links method.
+     *
      * @dataProvider get_convert_urls_into_links_test_cases
+     * @param string $text
+     * @param string $correctresult
      */
     public function test_convert_urls_into_links($text, $correctresult): void {
         $testablefilter = $this->get_testable_text_filter();
@@ -193,13 +201,15 @@ final class text_filter_test extends \basic_testcase {
     /**
      * Get a copy of the filter configured for testing.
      *
-     * @param array $args
+     * @param array ...$args
      * @return \filter_urltolink\text_filter
      */
     protected function get_testable_text_filter(...$args): text_filter {
         return new class extends text_filter {
+            // phpcs:ignore moodle.Commenting.MissingDocblock.MissingTestcaseMethodDescription
             public function __construct() {
             }
+            // phpcs:ignore moodle.Commenting.MissingDocblock.MissingTestcaseMethodDescription, Generic.CodeAnalysis.UselessOverridingMethod.Found
             public function convert_urls_into_links(&$text) {
                 parent::convert_urls_into_links($text);
             }