diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index 96e2f9d..0ca3b65 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -418,6 +418,7 @@ function template_preprocess_menu_tree(&$variables) {
       'attributes' => array(),
     );
     // @todo Remove backwards compatibility for $heading['class'].
+    //   https://www.drupal.org/node/2310341
     if (isset($heading['class'])) {
       $heading['attributes']['class'] = $heading['class'];
     }
diff --git a/core/lib/Drupal/Core/Utility/LinkGenerator.php b/core/lib/Drupal/Core/Utility/LinkGenerator.php
index 4912a05..54a2635 100644
--- a/core/lib/Drupal/Core/Utility/LinkGenerator.php
+++ b/core/lib/Drupal/Core/Utility/LinkGenerator.php
@@ -99,7 +99,9 @@ public function generateFromUrl($text, Url $url) {
       // drupal.active-link library know the path in a standardized manner.
       if (!isset($variables['options']['attributes']['data-drupal-link-system-path'])) {
         // @todo System path is deprecated - use the route name and parameters.
-        $variables['options']['attributes']['data-drupal-link-system-path'] = $url->getInternalPath();
+        $system_path = $url->getInternalPath();
+        // Special case for the front page.
+        $variables['options']['attributes']['data-drupal-link-system-path'] = $system_path != '' ?: '<front>';
       }
     }
 
diff --git a/core/misc/active-link.js b/core/misc/active-link.js
index b8edfe3..5bd12eb 100644
--- a/core/misc/active-link.js
+++ b/core/misc/active-link.js
@@ -28,9 +28,9 @@
       var originalSelectors = ['[data-drupal-link-system-path="' + path.currentPath + '"]'];
       var selectors;
 
-      // If this is the front page, we have to check for an empty path as well.
+      // If this is the front page, we have to check for the <front> path as well.
       if (path.isFront) {
-        originalSelectors.push('[data-drupal-link-system-path=""]');
+        originalSelectors.push('[data-drupal-link-system-path="<front>"]');
       }
 
       // Add language filtering.
diff --git a/core/modules/menu_ui/src/Plugin/Menu/LocalAction/MenuLinkAdd.php b/core/modules/menu_ui/src/Plugin/Menu/LocalAction/MenuLinkAdd.php
index b0238df..9fee161 100644
--- a/core/modules/menu_ui/src/Plugin/Menu/LocalAction/MenuLinkAdd.php
+++ b/core/modules/menu_ui/src/Plugin/Menu/LocalAction/MenuLinkAdd.php
@@ -28,8 +28,8 @@ public function getOptions(Request $request) {
       if ($request->attributes->has('_raw_variables')) {
         $raw_variables = $request->attributes->get('_raw_variables')->all();
       }
-      // @todo use RouteMatch instead of Request
-      // https://www.drupal.org/node/2294157
+      // @todo Use RouteMatch instead of Request.
+      //   https://www.drupal.org/node/2294157
       $options['query']['destination'] = \Drupal::urlGenerator()->generateFromRoute($route_name, $raw_variables);
     }
     return $options;
diff --git a/core/modules/system/src/Controller/SystemController.php b/core/modules/system/src/Controller/SystemController.php
index 8d5f2a7..c811e85 100644
--- a/core/modules/system/src/Controller/SystemController.php
+++ b/core/modules/system/src/Controller/SystemController.php
@@ -346,12 +346,12 @@ public function themesPage() {
    */
   public static function setLinkActiveClass(array $element, array $context) {
     $search_key_current_path = 'data-drupal-link-system-path="' . $context['path'] . '"';
-    $search_key_front = 'data-drupal-link-system-path';
+    $search_key_front = 'data-drupal-link-system-path="&lt;front&gt;"';
 
     // An active link's path is equal to the current path, so search the HTML
     // for an attribute with that value.
     $offset = 0;
-    while ((strpos($element['#markup'], $search_key_current_path, $offset) !== FALSE || ($context['front'] && strpos($element['#markup'], $search_key_front, $offset) !== FALSE))) {
+    while ((strpos($element['#markup'], 'data-drupal-link-system-path="' . $context['path'] . '"', $offset) !== FALSE || ($context['front'] && strpos($element['#markup'], 'data-drupal-link-system-path="&lt;front&gt;"', $offset) !== FALSE))) {
       $pos_current_path = strpos($element['#markup'], $search_key_current_path, $offset);
       $pos_front = strpos($element['#markup'], $search_key_front, $offset);
 
diff --git a/core/modules/system/src/Tests/Menu/LinksTest.php b/core/modules/system/src/Tests/Menu/LinksTest.php
index 3cb51e1..cbb9c8f 100644
--- a/core/modules/system/src/Tests/Menu/LinksTest.php
+++ b/core/modules/system/src/Tests/Menu/LinksTest.php
@@ -16,7 +16,8 @@
  *
  * @group Menu
  *
- * @todo: move this under menu_link_content module.
+ * @todo Move this under menu_link_content module.
+ *   https://www.drupal.org/node/2310353
  */
 class LinksTest extends WebTestBase {
 
@@ -172,7 +173,7 @@ function testMenuLinkReparenting($module = 'menu_test') {
     );
     $this->assertMenuLinkParents($links, $expected_hierarchy);
 
-    // @todo - figure out what makes sense to test in terms of automatic
+    // @todo Figure out what makes sense to test in terms of automatic
     //   re-parenting. https://www.drupal.org/node/2309531
   }
 
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index cae2567..93b37be 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -461,7 +461,8 @@ function toolbar_menu_navigation_links(array $tree) {
 
     $element->options['attributes']['id'] = 'toolbar-link-' . $id;
     $element->options['attributes']['class'][] = 'toolbar-icon';
-    // @todo Change to use the plugin ID as class as titles might change.
+    // @todo Change to use the plugin ID as class since titles might change.
+    //   https://www.drupal.org/node/2310365
     $element->options['attributes']['class'][] = 'toolbar-icon-' . strtolower(str_replace(' ', '-', $definition['title']));
     $element->options['attributes']['title'] = String::checkPlain($link->getDescription());
   }