43 files declare their use of AjaxResponse

AddFormBase.php in core/modules/media_library/src/Form/AddFormBase.php
AjaxCssForm.php in core/modules/ckeditor/tests/modules/src/Form/AjaxCssForm.php
AjaxRenderer.php in core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php
AjaxResponseSubscriber.php in core/lib/Drupal/Core/EventSubscriber/AjaxResponseSubscriber.php
AjaxResponseTest.php in core/tests/Drupal/Tests/Core/Ajax/AjaxResponseTest.php
AjaxTestController.php in core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php
AjaxTestDialogForm.php in core/modules/system/tests/modules/ajax_test/src/Form/AjaxTestDialogForm.php
AjaxTestImageEffect.php in core/modules/image/tests/modules/image_module_test/src/Plugin/ImageEffect/AjaxTestImageEffect.php
AjaxTestMessageCommandForm.php in core/modules/system/tests/modules/ajax_test/src/Form/AjaxTestMessageCommandForm.php
ajax_forms_test.module in core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module
Simpletest mock module for Ajax forms testing.
BigPipe.php in core/modules/big_pipe/src/Render/BigPipe.php
BigPipeResponseAttachmentsProcessorTest.php in core/modules/big_pipe/tests/src/Unit/Render/BigPipeResponseAttachmentsProcessorTest.php
BlockEntitySettingTrayForm.php in core/modules/settings_tray/src/Block/BlockEntitySettingTrayForm.php
Callbacks.php in core/modules/system/tests/modules/ajax_forms_test/src/Callbacks.php
CommandsTest.php in core/tests/Drupal/KernelTests/Core/Ajax/CommandsTest.php
ContentModerationConfigureEntityTypesForm.php in core/modules/content_moderation/src/Form/ContentModerationConfigureEntityTypesForm.php
DialogRenderer.php in core/lib/Drupal/Core/Render/MainContent/DialogRenderer.php
DummyAjaxWidget.php in core/modules/image/tests/modules/image_module_test/src/Plugin/Field/FieldWidget/DummyAjaxWidget.php
EarlyRenderingControllerWrapperSubscriber.php in core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php
EarlyRenderingTestController.php in core/modules/system/tests/modules/early_rendering_controller_test/src/EarlyRenderingTestController.php
EditorController.php in core/modules/editor/src/EditorController.php
EditorImageDialog.php in core/modules/editor/src/Form/EditorImageDialog.php
EditorLinkDialog.php in core/modules/editor/src/Form/EditorLinkDialog.php
EditorMediaDialog.php in core/modules/media/src/Form/EditorMediaDialog.php
FormAjaxResponseBuilder.php in core/lib/Drupal/Core/Form/FormAjaxResponseBuilder.php
FormAjaxResponseBuilderTest.php in core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php
FormAjaxSubscriber.php in core/lib/Drupal/Core/Form/EventSubscriber/FormAjaxSubscriber.php
JsAjaxTestForm.php in core/modules/system/tests/modules/js_ajax_test/src/Form/JsAjaxTestForm.php
LayoutRebuildTrait.php in core/modules/layout_builder/src/Controller/LayoutRebuildTrait.php
ManagedFile.php in core/modules/file/src/Element/ManagedFile.php
MediaLibraryEditorOpener.php in core/modules/media_library/src/MediaLibraryEditorOpener.php
MediaLibraryFieldWidgetOpener.php in core/modules/media_library/src/MediaLibraryFieldWidgetOpener.php
MediaLibraryWidget.php in core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
MediaTypeForm.php in core/modules/media/src/MediaTypeForm.php
ModalRenderer.php in core/lib/Drupal/Core/Render/MainContent/ModalRenderer.php
OffCanvasRenderer.php in core/lib/Drupal/Core/Render/MainContent/OffCanvasRenderer.php
QuickEditController.php in core/modules/quickedit/src/QuickEditController.php
ToolbarController.php in core/modules/toolbar/src/Controller/ToolbarController.php
ViewAjaxResponse.php in core/modules/views/src/Ajax/ViewAjaxResponse.php
ViewEditForm.php in core/modules/views_ui/src/ViewEditForm.php
ViewsFormBase.php in core/modules/views_ui/src/Form/Ajax/ViewsFormBase.php
ViewsUIController.php in core/modules/views_ui/src/Controller/ViewsUIController.php
WideModalRenderer.php in core/modules/system/tests/modules/dialog_renderer_test/src/Render/MainContent/WideModalRenderer.php

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