Issue #2445723 by dawehner, neclimdul: Use the $request format instead of the ContentNegotation

core/core.services.yml

core/lib/Drupal/Core/Ajax/AjaxSubscriber.php

...upal/Core/EventSubscriber/ContentControllerSubscriber.php

...rupal/Core/EventSubscriber/DefaultExceptionSubscriber.php

...upal/Core/EventSubscriber/HttpExceptionSubscriberBase.php

core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php

core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php

core/lib/Drupal/Core/Routing/RoutePreloader.php

...lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php

core/lib/Drupal/Core/StackMiddleware/PageCache.php

core/modules/hal/hal.services.yml

core/modules/hal/src/HalServiceProvider.php

core/modules/hal/src/HalSubscriber.php

core/modules/rest/src/Plugin/views/display/RestExport.php

core/modules/rest/tests/src/Unit/CollectRoutesTest.php

core/modules/system/src/Tests/Bootstrap/PageCacheTest.php

...sts/Drupal/Tests/Core/Routing/AcceptHeaderMatcherTest.php

core/tests/Drupal/Tests/Core/Routing/RoutePreloaderTest.php