diff -u b/core/modules/language/language.module b/core/modules/language/language.module
--- b/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -59,8 +59,13 @@
       return $output;
 
     case 'block.admin_edit':
+      if (($block = $request->attributes->get('block')) && $block->get('plugin') == 'language_block:language_interface') {
+        return '<p>' . t('With multiple languages added, registered users can select their preferred language and authors can assign a specific language to content.') . '</p>';
+      }
+      break;
+
     case 'block.admin_add':
-      if ($request->attributes->get('plugin_id') == 'language:language_interface') {
+      if ($request->attributes->get('plugin_id') == 'language_block:language_interface') {
         return '<p>' . t('With multiple languages added, registered users can select their preferred language and authors can assign a specific language to content.') . '</p>';
       }
       break;
diff -u b/core/modules/node/node.module b/core/modules/node/node.module
--- b/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -124,16 +124,18 @@
     case 'node.type_add':
       return '<p>' . t('Individual content types can have different fields, behaviors, and permissions assigned to them.') . '</p>';
 
+    case 'field_ui.form_display_overview_node':
     case 'field_ui.form_display_overview_form_mode_node':
       $type = $request->attributes->get('node_type');
       return '<p>' . t('Content items can be edited using different form modes. Here, you can define which fields are shown and hidden when %type content is edited in each form mode, and define how the field form widgets are displayed in each form mode.', array('%type' => $type->label())) . '</p>' ;
 
+    case 'field_ui.display_overview_node':
     case 'field_ui.display_overview_view_mode_node':
       $type = $request->attributes->get('node_type');
       return '<p>' . t('Content items can be displayed using different view modes: Teaser, Full content, Print, RSS, etc. <em>Teaser</em> is a short format that is typically used in lists of multiple content items. <em>Full content</em> is typically used when the content is displayed on its own page.') . '</p>' .
         '<p>' . t('Here, you can define which fields are shown and hidden when %type content is displayed in each view mode, and define how the fields are displayed in each view mode.', array('%type' => $type->label())) . '</p>';
 
-    case 'node.revision.overview':
+    case 'node.revision_overview':
       return '<p>' . t('Revisions allow you to track differences between multiple versions of your content, and revert back to older versions.') . '</p>';
 
     case 'node.page_edit':
diff -u b/core/modules/system/system.module b/core/modules/system/system.module
--- b/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -112,7 +112,7 @@
     case 'system.theme_settings':
       return '<p>' . t('These options control the default display settings for your entire site, across all themes. Unless they have been overridden by a specific theme, these settings will be used.') . '</p>';
 
-    case 'system.modules':
+    case 'system.modules_list':
       $output = '<p>' . t('Download additional <a href="@modules">contributed modules</a> to extend Drupal\'s functionality.', array('@modules' => 'http://drupal.org/project/modules')) . '</p>';
       if (\Drupal::moduleHandler()->moduleExists('update')) {
         if (update_manager_access()) {