.../src/Functional/FileUploadResourceTestBase.php  | 22 ----------------------
 .../EventSubscriber/ResourceResponseSubscriber.php |  6 +++---
 core/modules/rest/src/Routing/ResourceRoutes.php   | 10 +---------
 3 files changed, 4 insertions(+), 34 deletions(-)

diff --git a/core/modules/file/tests/src/Functional/FileUploadResourceTestBase.php b/core/modules/file/tests/src/Functional/FileUploadResourceTestBase.php
index 15cfa09..29af273 100644
--- a/core/modules/file/tests/src/Functional/FileUploadResourceTestBase.php
+++ b/core/modules/file/tests/src/Functional/FileUploadResourceTestBase.php
@@ -124,13 +124,6 @@ protected function setUpAuthorization($method) {
   /**
    * {@inheritdoc}
    */
-  protected function assertResponseWhenMissingAuthentication(ResponseInterface $response) {
-    // TODO: Implement assertResponseWhenMissingAuthentication() method.
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   protected function assertNormalizationEdgeCases($method, Url $url, array $request_options) {
     // TODO: Implement assertNormalizationEdgeCases() method.
   }
@@ -138,26 +131,11 @@ protected function assertNormalizationEdgeCases($method, Url $url, array $reques
   /**
    * {@inheritdoc}
    */
-  protected function assertAuthenticationEdgeCases($method, Url $url, array $request_options) {
-    // TODO: Implement assertAuthenticationEdgeCases() method.
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   protected function getExpectedUnauthorizedAccessMessage($method) {
     // TODO: Implement getExpectedUnauthorizedAccessMessage() method.
   }
 
   /**
-   * {@inheritdoc}
-   */
-  protected function getExpectedBcUnauthorizedAccessMessage($method) {
-    // TODO: Implement getExpectedBcUnauthorizedAccessMessage() method.
-  }
-
-
-  /**
    * Tests using the file upload POST route.
    */
   public function testPostFileUpload() {
diff --git a/core/modules/rest/src/EventSubscriber/ResourceResponseSubscriber.php b/core/modules/rest/src/EventSubscriber/ResourceResponseSubscriber.php
index 58a863e..8f90819 100644
--- a/core/modules/rest/src/EventSubscriber/ResourceResponseSubscriber.php
+++ b/core/modules/rest/src/EventSubscriber/ResourceResponseSubscriber.php
@@ -96,7 +96,7 @@ public function getResponseFormat(RouteMatchInterface $route_match, Request $req
     $route = $route_match->getRouteObject();
     $acceptable_request_formats = $route->hasRequirement('_format') ? explode('|', $route->getRequirement('_format')) : [];
     $acceptable_content_type_formats = $route->hasRequirement('_content_type_format') ? explode('|', $route->getRequirement('_content_type_format')) : [];
-    $fallback_acceptable_formats = $request->isMethodCacheable() ? $acceptable_request_formats : $acceptable_content_type_formats;
+    $acceptable_formats = $request->isMethodCacheable() ? $acceptable_request_formats : $acceptable_content_type_formats;
 
     $requested_format = $request->getRequestFormat();
     $content_type_format = $request->getContentType();
@@ -114,8 +114,8 @@ public function getResponseFormat(RouteMatchInterface $route_match, Request $req
       return $content_type_format;
     }
     // Otherwise, use the first acceptable format.
-    elseif (!empty($fallback_acceptable_formats)) {
-      return $fallback_acceptable_formats[0];
+    elseif (!empty($acceptable_formats)) {
+      return $acceptable_formats[0];
     }
     // Sometimes, there are no acceptable formats, e.g. DELETE routes.
     else {
diff --git a/core/modules/rest/src/Routing/ResourceRoutes.php b/core/modules/rest/src/Routing/ResourceRoutes.php
index 33c21de..c5e1fa0 100644
--- a/core/modules/rest/src/Routing/ResourceRoutes.php
+++ b/core/modules/rest/src/Routing/ResourceRoutes.php
@@ -109,18 +109,10 @@ protected function getRoutesForResourceConfig(RestResourceConfigInterface $rest_
         }
 
         // The configuration has been validated, so we update the route to:
-        // - set the allowed response body content types/formats for methods
-        //   that may send response bodies
         // - set the allowed request body content types/formats for methods that
         //   allow request bodies to be sent
         // - set the allowed authentication providers
-        // @todo Remove this in Drupal 9. @RestResource plugins should be
-        //       given the RESTResourceConfig entity, and should generate the
-        //       appropriate routes in ::routes() based on that. But doing so
-        //       would be a BC break. This is the next best thing we can do.
-        if (in_array($method, ['GET', 'HEAD', 'POST', 'PUT', 'PATCH'], TRUE)) {
-          $route->addRequirements(['_format' => implode('|', $rest_resource_config->getFormats($method))]);
-        }
+        // @todo clean this up further in https://www.drupal.org/node/2858482
         if (in_array($method, ['POST', 'PATCH', 'PUT'], TRUE) && !$route->hasRequirement('_content_type_format')) {
           $route->addRequirements(['_content_type_format' => implode('|', $rest_resource_config->getFormats($method))]);
         }