25 files declare their use of MainContentViewSubscriber

AjaxHelperTrait.php in core/lib/Drupal/Core/Ajax/AjaxHelperTrait.php
AreaDisplayLinkTest.php in core/modules/views/tests/src/Kernel/Handler/AreaDisplayLinkTest.php
BlockLibraryController.php in core/modules/block/src/Controller/BlockLibraryController.php
ContentModerationConfigureEntityTypesForm.php in core/modules/content_moderation/src/Form/ContentModerationConfigureEntityTypesForm.php
DisplayLink.php in core/modules/views/src/Plugin/views/area/DisplayLink.php
DynamicPageCacheIntegrationTest.php in core/modules/dynamic_page_cache/tests/src/Functional/DynamicPageCacheIntegrationTest.php
EntityCacheTagsTestBase.php in core/modules/system/tests/src/Functional/Entity/EntityCacheTagsTestBase.php
FormAjaxSubscriber.php in core/lib/Drupal/Core/Form/EventSubscriber/FormAjaxSubscriber.php
FormBuilder.php in core/lib/Drupal/Core/Form/FormBuilder.php
FrameworkTest.php in core/modules/system/tests/src/Functional/Ajax/FrameworkTest.php
MenuUiTest.php in core/modules/menu_ui/tests/src/Functional/MenuUiTest.php
NodeBlockFunctionalTest.php in core/modules/node/tests/src/Functional/NodeBlockFunctionalTest.php
OffCanvasDialogTest.php in core/modules/system/tests/src/Functional/Ajax/OffCanvasDialogTest.php
PageCacheTagsIntegrationTest.php in core/modules/page_cache/tests/src/Functional/PageCacheTagsIntegrationTest.php
RenderWebTest.php in core/modules/system/tests/src/Functional/Common/RenderWebTest.php
RouterTest.php in core/modules/system/tests/src/Functional/Routing/RouterTest.php
StackSessionHandlerIntegrationTest.php in core/modules/system/tests/src/Functional/Session/StackSessionHandlerIntegrationTest.php
StorageTest.php in core/modules/system/tests/src/Functional/Form/StorageTest.php
StyleSerializerEntityTest.php in core/modules/rest/tests/src/Functional/Views/StyleSerializerEntityTest.php
TokenReplaceWebTest.php in core/modules/system/tests/src/Functional/System/TokenReplaceWebTest.php
ToolbarAdminMenuTest.php in core/modules/toolbar/tests/src/Functional/ToolbarAdminMenuTest.php
ToolbarCacheContextsTest.php in core/modules/toolbar/tests/src/Functional/ToolbarCacheContextsTest.php
TrackerTest.php in core/modules/tracker/tests/src/Functional/TrackerTest.php
ViewAjaxController.php in core/modules/views/src/Controller/ViewAjaxController.php
ViewAjaxTest.php in core/modules/views/tests/src/Functional/ViewAjaxTest.php

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