diff --git a/src/event/RegisteredListenerCache.php b/src/event/RegisteredListenerCache.php
index 1b675c716..e5e315546 100644
--- a/src/event/RegisteredListenerCache.php
+++ b/src/event/RegisteredListenerCache.php
@@ -23,6 +23,9 @@ declare(strict_types=1);
 
 namespace pocketmine\event;
 
+/**
+ * @internal
+ */
 final class RegisteredListenerCache{
 
 	/**