diff --git a/lib/classes/component.php b/lib/classes/component.php
index 5ea3dfd4996..489ed1f833e 100644
--- a/lib/classes/component.php
+++ b/lib/classes/component.php
@@ -1025,7 +1025,7 @@ $cache = '.var_export($cache, true).';
      * Note: this does not verify the validity of plugin or type names.
      *
      * @param string $component
-     * @return array as (string)$type => (string)$plugin
+     * @return array two-items list of [(string)type, (string|null)name]
      */
     public static function normalize_component($component) {
         if ($component === 'moodle' or $component === 'core' or $component === '') {
diff --git a/lib/deprecatedlib.php b/lib/deprecatedlib.php
index 1e92aa4f695..e39324e35a7 100644
--- a/lib/deprecatedlib.php
+++ b/lib/deprecatedlib.php
@@ -214,7 +214,7 @@ function get_plugin_directory($plugintype, $name) {
  * @deprecated since 2.6, use core_component::normalize_component()
  *
  * @param string $component
- * @return array as (string)$type => (string)$plugin
+ * @return array two-items list of [(string)type, (string|null)name]
  */
 function normalize_component($component) {