Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/system/src/MenuInterface.php

@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\MenuInterface.
+ */
+
+namespace Drupal\system;
+
+use Drupal\Core\Config\Entity\ConfigEntityInterface;
+
+/**
+ * Provides an interface defining a menu entity.
+ */
+interface MenuInterface extends ConfigEntityInterface {
+
+  /**
+   * Returns the description of the menu.
+   *
+   * @return string
+   *   Description of the menu.
+   */
+  public function getDescription();
+
+  /**
+   * Determines if this menu is locked.
+   *
+   * @return bool
+   *   TRUE if the menu is locked, FALSE otherwise.
+   */
+  public function isLocked();
+
+}