diff --git a/cache/classes/definition.php b/cache/classes/definition.php
index 588566f1f9c..1427d93ecb8 100644
--- a/cache/classes/definition.php
+++ b/cache/classes/definition.php
@@ -14,20 +14,6 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
-/**
- * Cache definition class
- *
- * This file is part of Moodle's cache API, affectionately called MUC.
- * It contains the components that are requried in order to use caching.
- *
- * @package    core
- * @category   cache
- * @copyright  2012 Sam Hemelryk
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-defined('MOODLE_INTERNAL') || die();
-
 /**
  * The cache definition class.
  *
diff --git a/lib/db/legacyclasses.php b/lib/db/legacyclasses.php
index f4b99b6aaca..0cedfa86083 100644
--- a/lib/db/legacyclasses.php
+++ b/lib/db/legacyclasses.php
@@ -53,6 +53,7 @@ $legacyclasses = [
     // Cache API.
     \cache::class => 'cache.php',
     \cache_application::class => 'application_cache.php',
+    \cache_definition::class => 'definition.php',
     \cache_request::class => 'request_cache.php',
     \cache_session::class => 'session_cache.php',
     \cache_cached_object::class => 'cached_object.php',