diff --git a/core/modules/book/lib/Drupal/book/BookBreadcrumbBuilder.php b/core/modules/book/lib/Drupal/book/BookBreadcrumbBuilder.php
index c38d9d9..dd4f919 100644
--- a/core/modules/book/lib/Drupal/book/BookBreadcrumbBuilder.php
+++ b/core/modules/book/lib/Drupal/book/BookBreadcrumbBuilder.php
@@ -9,14 +9,13 @@
 
 use Drupal\Core\Access\AccessManager;
 use Drupal\Core\Breadcrumb\BreadcrumbBuilderBase;
-use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
 use Drupal\Core\Entity\EntityManager;
 use Drupal\node\NodeInterface;
 
 /**
  * Provides a breadcrumb builder for nodes in a book.
  */
-class BookBreadcrumbBuilder extends BreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
+class BookBreadcrumbBuilder extends BreadcrumbBuilderBase {
 
   /**
    * The menu link storage controller.
diff --git a/core/modules/comment/lib/Drupal/comment/CommentBreadcrumbBuilder.php b/core/modules/comment/lib/Drupal/comment/CommentBreadcrumbBuilder.php
index 785003c..dd40084 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentBreadcrumbBuilder.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentBreadcrumbBuilder.php
@@ -8,14 +8,13 @@
 namespace Drupal\comment;
 
 use Drupal\Core\Breadcrumb\BreadcrumbBuilderBase;
-use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
 use Drupal\Core\Entity\EntityManager;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 
 /**
  * Class to define the comment breadcrumb builder.
  */
-class CommentBreadcrumbBuilder extends BreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
+class CommentBreadcrumbBuilder extends BreadcrumbBuilderBase {
 
   /**
    * Stores the Entity manager service.
diff --git a/core/modules/forum/lib/Drupal/forum/ForumBreadcrumbBuilder.php b/core/modules/forum/lib/Drupal/forum/ForumBreadcrumbBuilder.php
index 61cbe38..fb133a8 100644
--- a/core/modules/forum/lib/Drupal/forum/ForumBreadcrumbBuilder.php
+++ b/core/modules/forum/lib/Drupal/forum/ForumBreadcrumbBuilder.php
@@ -8,7 +8,6 @@
 namespace Drupal\forum;
 
 use Drupal\Core\Breadcrumb\BreadcrumbBuilderBase;
-use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Entity\EntityManager;
 use Drupal\forum\ForumManagerInterface;
@@ -17,7 +16,7 @@
 /**
  * Class to define the forum breadcrumb builder.
  */
-class ForumBreadcrumbBuilder extends BreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
+class ForumBreadcrumbBuilder extends BreadcrumbBuilderBase {
 
   /**
    * Configuration object for this builder.
diff --git a/core/modules/system/lib/Drupal/system/PathBasedBreadcrumbBuilder.php b/core/modules/system/lib/Drupal/system/PathBasedBreadcrumbBuilder.php
index 174680e..5c0173e 100644
--- a/core/modules/system/lib/Drupal/system/PathBasedBreadcrumbBuilder.php
+++ b/core/modules/system/lib/Drupal/system/PathBasedBreadcrumbBuilder.php
@@ -8,7 +8,6 @@
 namespace Drupal\system;
 
 use Drupal\Core\Breadcrumb\BreadcrumbBuilderBase;
-use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Controller\TitleResolverInterface;
 use Drupal\Core\Entity\EntityManager;
@@ -24,7 +23,7 @@
 /**
  * Class to define the menu_link breadcrumb builder.
  */
-class PathBasedBreadcrumbBuilder extends BreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
+class PathBasedBreadcrumbBuilder extends BreadcrumbBuilderBase {
 
   /**
    * The current request.