diff --git a/core/lib/Drupal/Core/Entity/ContentEntityType.php b/core/lib/Drupal/Core/Entity/ContentEntityType.php
index 14f7ee2..2bd05c8 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityType.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityType.php
@@ -10,7 +10,7 @@
 /**
  * Defines a config entity type annotation object.
  */
-class ContentEntityType extends EntityType {
+class ContentEntityType extends EntityType implements ContentEntityTypeInterface {
 
   /**
    * {@inheritdoc}
diff --git a/core/lib/Drupal/Core/Entity/ContentEntityTypeInterface.php b/core/lib/Drupal/Core/Entity/ContentEntityTypeInterface.php
new file mode 100644
index 0000000..79f0ccf
--- /dev/null
+++ b/core/lib/Drupal/Core/Entity/ContentEntityTypeInterface.php
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Entity\ContentEntityTypeInterface.
+ */
+
+namespace Drupal\Core\Entity;
+
+/**
+ * Provides an interface for a content entity type and its metadata.
+ */
+interface ContentEntityTypeInterface extends EntityTypeInterface {
+}