diff --git a/core/lib/Drupal/Core/Entity/Annotation/EntityType.php b/core/lib/Drupal/Core/Entity/Annotation/EntityType.php
index 2c27ccb..df109fc 100644
--- a/core/lib/Drupal/Core/Entity/Annotation/EntityType.php
+++ b/core/lib/Drupal/Core/Entity/Annotation/EntityType.php
@@ -12,6 +12,14 @@
 /**
  * Defines an Entity type annotation object.
  *
+ * Entity type plugins use an object-based annotation method, rather than an
+ * array-type annotation method (as commonly used on other annotation types).
+ * The annotation properties of entity types are found on
+ * \Drupal\Core\Entity\EntityType and are accessed using get/set methods defined
+ * in \Drupal\Core\Entity\EntityTypeInterface.
+ *
+ * @see https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Entity%21Annotation%21EntityType.php/class/EntityType/8
+ *
  * @Annotation
  */
 class EntityType extends Plugin {