diff --git a/core/modules/block/block.api.php b/core/modules/block/block.api.php
index f892c80..93e90df 100644
--- a/core/modules/block/block.api.php
+++ b/core/modules/block/block.api.php
@@ -50,7 +50,7 @@ function hook_block_view_alter(array &$build, \Drupal\block\BlockPluginInterface
  * id, regardless of whether the plugin supports derivatives. For example, for
  * the \Drupal\system\Plugin\block\block\SystemPoweredByBlock block, this would
  * be 'system_powered_by_block' as per that class's annotation. And for the
- * \Drupal\menu\Plugin\Block\MenuBlock block, it would be 'menu_menu_block' as
+ * \Drupal\menu\Plugin\Block\MenuBlock block, it would be 'system_menu_block' as
  * per that class's annotation, regardless of which menu the derived block is
  * for.
  *
diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 18f1c7f..f405cb2 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -589,7 +589,7 @@ function block_user_role_delete($role) {
  */
 function block_menu_delete($menu) {
   foreach (entity_load_multiple('block') as $block) {
-    if ($block->get('plugin') == 'menu_menu_block:' . $menu->id()) {
+    if ($block->get('plugin') == 'system_menu_block:' . $menu->id()) {
       $block->delete();
     }
   }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
index 260e513..c719fbe 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
@@ -39,7 +39,7 @@ function setUp() {
     \Drupal::state()->set('block_test.content', $current_content);
 
     // Enable our test blocks.
-    $this->drupalPlaceBlock('menu_menu_block:tools');
+    $this->drupalPlaceBlock('system_menu_block:tools');
     $this->drupalPlaceBlock('test_html_id', array('machine_name' => 'test_id_block'));
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
index 75266a8..cf50e78 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
@@ -38,7 +38,7 @@ function testBlockThemeHookSuggestions() {
     // and generates possibilities for each level of derivative.
     // @todo Clarify this comment.
     $block = entity_create('block', array(
-      'plugin' => 'menu_menu_block:admin',
+      'plugin' => 'system_menu_block:admin',
       'region' => 'footer',
       'id' => \Drupal::config('system.theme')->get('default') . '.machinename',
     ));
@@ -51,7 +51,7 @@ function testBlockThemeHookSuggestions() {
     // Test adding a class to the block content.
     $variables['content_attributes']['class'][] = 'test-class';
     template_preprocess_block($variables);
-    $this->assertEqual($variables['theme_hook_suggestions'], array('block__system', 'block__menu_menu_block', 'block__menu_menu_block__admin', 'block__machinename'));
+    $this->assertEqual($variables['theme_hook_suggestions'], array('block__system', 'block__system_menu_block', 'block__system_menu_block__admin', 'block__machinename'));
     $this->assertEqual($variables['content_attributes']['class'], array('test-class', 'content'), 'Default .content class added to block content_attributes');
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
index e295149..9921f8e 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
@@ -50,7 +50,7 @@ function setUp() {
       array(
         'label' => 'Tools',
         'tr' => '5',
-        'plugin_id' => 'menu_menu_block:tools',
+        'plugin_id' => 'system_menu_block:tools',
         'settings' => array('region' => 'sidebar_second', 'machine_name' => 'tools'),
         'test_weight' => '-1',
       ),
diff --git a/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php b/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
index bdd0fbb..5a2da65 100644
--- a/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
+++ b/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
@@ -165,7 +165,7 @@ function addCustomMenu() {
     $this->assertText($label);
 
     // Enable the block.
-    $this->drupalPlaceBlock('menu_menu_block:' . $menu_name);
+    $this->drupalPlaceBlock('system_menu_block:' . $menu_name);
     return menu_load($menu_name);
   }
 
@@ -407,7 +407,7 @@ function testSystemMenuRename() {
   public function testBlockContextualLinks() {
     $this->drupalLogin($this->drupalCreateUser(array('administer menu', 'access contextual links', 'administer blocks')));
     $this->addMenuLink();
-    $block = $this->drupalPlaceBlock('menu_menu_block:tools', array('label' => 'Tools', 'module' => 'system'));
+    $block = $this->drupalPlaceBlock('system_menu_block:tools', array('label' => 'Tools', 'module' => 'system'));
     $this->drupalGet('test-page');
 
     $id = 'block:admin/structure/block/manage:' . $block->id() . ':|menu:admin/structure/menu/manage:tools:';
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index 8fb475d..bca49fc 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -382,9 +382,9 @@ function _menu_parents_recurse($tree, $menu_name, $indent, &$options, $exclude,
 }
 
 /**
- * Implements hook_block_view_BASE_BLOCK_ID_alter() for 'menu_menu_block'.
+ * Implements hook_block_view_BASE_BLOCK_ID_alter() for 'system_menu_block'.
  */
-function menu_block_view_menu_menu_block_alter(array &$build, BlockPluginInterface $block) {
+function menu_block_view_system_menu_block_alter(array &$build, BlockPluginInterface $block) {
   // Add contextual links for system menu blocks.
   $menus = menu_list_system_menus();
   list(, $menu_name) = explode(':', $block->getPluginId());
diff --git a/core/modules/system/lib/Drupal/system/Plugin/Block/MenuBlock.php b/core/modules/system/lib/Drupal/system/Plugin/Block/MenuBlock.php
index a6ea51a..8f733a3 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/Block/MenuBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/Block/MenuBlock.php
@@ -15,7 +15,7 @@
  * Provides a generic Menu block.
  *
  * @Block(
- *   id = "menu_menu_block",
+ *   id = "system_menu_block",
  *   admin_label = @Translation("Menu"),
  *   derivative = "Drupal\system\Plugin\Derivative\MenuBlock"
  * )
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
index 3e1259f..5be7001 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
@@ -48,9 +48,9 @@ function setUp() {
       'machine_name' => 'system_menu_tools',
       'region' => 'content',
     );
-    $this->drupalPlaceBlock('menu_menu_block:tools', $settings);
+    $this->drupalPlaceBlock('system_menu_block:tools', $settings);
     $settings['theme'] = \Drupal::config('system.theme')->get('admin');
-    $this->drupalPlaceBlock('menu_menu_block:tools', $settings);
+    $this->drupalPlaceBlock('system_menu_block:tools', $settings);
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
index 392cbdb..230357a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
@@ -65,7 +65,7 @@ function setUp() {
       ->set('admin', $this->admin_theme)
       ->save();
     theme_disable(array($this->alternate_theme));
-    $this->drupalPlaceBlock('menu_menu_block:tools');
+    $this->drupalPlaceBlock('system_menu_block:tools');
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
index 715ad69..111c118 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
@@ -35,8 +35,8 @@ function setUp() {
 
     // This test puts menu links in the Tools and Administration menus and then
     // tests for their presence on the page.
-    $this->drupalPlaceBlock('menu_menu_block:tools');
-    $this->drupalPlaceBlock('menu_menu_block:admin');
+    $this->drupalPlaceBlock('system_menu_block:tools');
+    $this->drupalPlaceBlock('system_menu_block:admin');
   }
 
   /**
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 4436a5e..986f710 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2293,7 +2293,7 @@ function system_preprocess_block(&$variables) {
       $variables['attributes']['role'] = 'complementary';
       break;
 
-    case 'menu_menu_block':
+    case 'system_menu_block':
       $menus = menu_list_system_menus();
       if (isset($menus[$derivative])) {
         $variables['attributes']['role'] = 'navigation';
diff --git a/core/profiles/minimal/config/block.block.stark.admin.yml b/core/profiles/minimal/config/block.block.stark.admin.yml
index c623a53..e22ff72 100644
--- a/core/profiles/minimal/config/block.block.stark.admin.yml
+++ b/core/profiles/minimal/config/block.block.stark.admin.yml
@@ -3,7 +3,7 @@ weight: '1'
 status: '1'
 langcode: en
 region: sidebar_first
-plugin: 'menu_menu_block:admin'
+plugin: 'system_menu_block:admin'
 settings:
   label: Administration
   module: system
diff --git a/core/profiles/minimal/config/block.block.stark.tools.yml b/core/profiles/minimal/config/block.block.stark.tools.yml
index 4159142..c53d934 100644
--- a/core/profiles/minimal/config/block.block.stark.tools.yml
+++ b/core/profiles/minimal/config/block.block.stark.tools.yml
@@ -3,7 +3,7 @@ weight: '0'
 status: '1'
 langcode: en
 region: sidebar_first
-plugin: 'menu_menu_block:tools'
+plugin: 'system_menu_block:tools'
 settings:
   label: Tools
   module: system
diff --git a/core/profiles/standard/config/block.block.bartik.footer.yml b/core/profiles/standard/config/block.block.bartik.footer.yml
index a8519eb..a770dae 100644
--- a/core/profiles/standard/config/block.block.bartik.footer.yml
+++ b/core/profiles/standard/config/block.block.bartik.footer.yml
@@ -3,7 +3,7 @@ weight: '0'
 status: '1'
 langcode: en
 region: footer
-plugin: 'menu_menu_block:footer'
+plugin: 'system_menu_block:footer'
 settings:
   label: 'Footer menu'
   module: system
diff --git a/core/profiles/standard/config/block.block.bartik.tools.yml b/core/profiles/standard/config/block.block.bartik.tools.yml
index 496e87a..2855ce2 100644
--- a/core/profiles/standard/config/block.block.bartik.tools.yml
+++ b/core/profiles/standard/config/block.block.bartik.tools.yml
@@ -3,7 +3,7 @@ weight: '0'
 status: '1'
 langcode: en
 region: sidebar_first
-plugin: 'menu_menu_block:tools'
+plugin: 'system_menu_block:tools'
 settings:
   label: Tools
   module: system
diff --git a/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php b/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
index b17704a..d416dd6 100644
--- a/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
+++ b/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
@@ -37,7 +37,7 @@ function testStandard() {
     $admin = $this->drupalCreateUser(array('administer blocks'));
     $this->drupalLogin($admin);
     // Configure the block.
-    $this->drupalGet('admin/structure/block/add/menu_menu_block:main/bartik');
+    $this->drupalGet('admin/structure/block/add/system_menu_block:main/bartik');
     $this->drupalPost(NULL, array(
       'region' => 'sidebar_first',
       'machine_name' => 'main_navigation',