diff --git a/core/modules/menu/lib/Drupal/menu/MenuListController.php b/core/modules/menu/lib/Drupal/menu/MenuListController.php
index 881c3a1..87dacd5 100644
--- a/core/modules/menu/lib/Drupal/menu/MenuListController.php
+++ b/core/modules/menu/lib/Drupal/menu/MenuListController.php
@@ -1,7 +1,7 @@
 <?php
 
 /**
- * Definition of Drupal\contact\MenuListController.
+ * Contains \Drupal\contact\MenuListController.
  */
 
 namespace Drupal\menu;
diff --git a/core/modules/menu/menu.admin.inc b/core/modules/menu/menu.admin.inc
index 1339379..bf7d4c1 100644
--- a/core/modules/menu/menu.admin.inc
+++ b/core/modules/menu/menu.admin.inc
@@ -6,7 +6,7 @@
  */
 
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
-use Drupal\menu\Plugin\Core\Entity\Menu;
+use Drupal\system\Plugin\Core\Entity\Menu;
 
 /**
  * Menu callback which shows an overview page of all the custom menus and their descriptions.
diff --git a/core/modules/menu/menu.install b/core/modules/menu/menu.install
index 2fa8163..56d45f3 100644
--- a/core/modules/menu/menu.install
+++ b/core/modules/menu/menu.install
@@ -6,64 +6,6 @@
  */
 
 /**
- * Implements hook_schema().
- *
-function menu_schema() {
-  $schema['menu_custom'] = array(
-    'description' => 'Holds definitions for top-level custom menus (for example, Main navigation menu).',
-    'fields' => array(
-      'menu_name' => array(
-        'type' => 'varchar',
-        'length' => 32,
-        'not null' => TRUE,
-        'default' => '',
-        'description' => 'Primary Key: Unique key for menu. This is used as a block delta so length is 32.',
-      ),
-      'title' => array(
-        'type' => 'varchar',
-        'length' => 255,
-        'not null' => TRUE,
-        'default' => '',
-        'description' => 'Menu title; displayed at top of block.',
-        'translatable' => TRUE,
-      ),
-      'description' => array(
-        'type' => 'text',
-        'not null' => FALSE,
-        'description' => 'Menu description.',
-        'translatable' => TRUE,
-      ),
-    ),
-    'primary key' => array('menu_name'),
-  );
-
-  return $schema;
-}*/
-
-/**
- * Implements hook_install().
- *
-function menu_install() {
-  $system_menus = menu_list_system_menus();
-  $t = get_t();
-  $descriptions = array(
-    'tools' => $t('Contains links for site visitors. Some modules add their links here.'),
-    'account' => $t('Links related to the user account.'),
-    'admin' => $t('Contains links to administrative tasks.'),
-    'main' => $t('Use this for linking to the main site sections.'),
-    'footer' => $t('Use this for linking to site information.'),
-  );
-  foreach ($system_menus as $menu_name => $title) {
-    $menu = array(
-      'menu_name' => $menu_name,
-      'title' => $t($title),
-      'description' => $descriptions[$menu_name],
-    );
-    menu_save($menu);
-  }
-}*/
-
-/**
  * Implements hook_uninstall().
  */
 function menu_uninstall() {
@@ -142,11 +84,3 @@ function menu_update_8004() {
       ->save();
   }
 }
-
-/**
- * Drop the {menu_custom} table.
- */
-function menu_update_8005() {
-  db_drop_table('menu_custom');
-}
-
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index 2423f1b..4c65948 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -13,7 +13,7 @@
 
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Drupal\node\Plugin\Core\Entity\Node;
-use Drupal\menu\Plugin\Core\Entity\Menu;
+use Drupal\system\Plugin\Core\Entity\Menu;
 use Drupal\Core\Config\Entity\ConfigEntityBase;
 
 /**
@@ -164,7 +164,7 @@ function menu_menu() {
 /**
  * Entity URI callback.
  *
- * @param Drupal\menu\Plugin\Core\Entity\Menu $menu
+ * @param Drupal\system\Plugin\Core\Entity\Menu $menu
  *   A Menu entity.
  */
 function menu_uri(Menu $menu) {
@@ -284,7 +284,7 @@ function menu_load($menu_name) {
 /**
  * Save a custom menu.
  *
- * @param Drupal\menu\Plugin\Core\Entity\Menu $menu
+ * @param Drupal\system\Plugin\Core\Entity\Menu $menu
  *   An array representing a custom menu:
  *   - menu_name: The unique name of the custom menu (composed of lowercase
  *     letters, numbers, and hyphens).
@@ -332,7 +332,7 @@ function menu_save($menu_array) {
  * function should usually be called from a user interface (form submit) handler
  * only, which allows the user to confirm the action.
  *
- * @param Drupal\menu\Plugin\Core\Entity\Menu $menu
+ * @param Drupal\system\Plugin\Core\Entity\Menu $menu
  *   An array representing a custom menu:
  *   - menu_name: The unique name of the custom menu.
  *   - title: The human readable menu title.
diff --git a/core/modules/menu/lib/Drupal/menu/Plugin/Core/Entity/Menu.php b/core/modules/system/lib/Drupal/system/Plugin/Core/Entity/Menu.php
similarity index 91%
rename from core/modules/menu/lib/Drupal/menu/Plugin/Core/Entity/Menu.php
rename to core/modules/system/lib/Drupal/system/Plugin/Core/Entity/Menu.php
index 6365073..4cbf898 100644
--- a/core/modules/menu/lib/Drupal/menu/Plugin/Core/Entity/Menu.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/Core/Entity/Menu.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Definition of Drupal\menu\Plugin\Core\Entity\Menu.
+ * Contains \Drupal\system\Plugin\Core\Entity\Menu.
  */
 
-namespace Drupal\menu\Plugin\Core\Entity;
+namespace Drupal\system\Plugin\Core\Entity;
 
 use Drupal\Core\Config\Entity\ConfigEntityBase;
 use Drupal\Core\Annotation\Plugin;