55 files declare their use of Plugin

Action.php in core/lib/Drupal/Core/Action/Attribute/Action.php
Archiver.php in core/lib/Drupal/Core/Archiver/Attribute/Archiver.php
AttributeBridgeDecoratorTest.php in core/tests/Drupal/Tests/Component/Plugin/Discovery/AttributeBridgeDecoratorTest.php
AttributeClassDiscovery.php in core/lib/Drupal/Component/Plugin/Discovery/AttributeClassDiscovery.php
AttributeDiscoveryTest1.php in core/tests/Drupal/Tests/Component/Plugin/Attribute/Fixtures/Plugins/PluginNamespace/AttributeDiscoveryTest1.php
Block.php in core/lib/Drupal/Core/Block/Attribute/Block.php
CKEditor5AspectsOfCKEditor5Plugin.php in core/modules/ckeditor5/src/Attribute/CKEditor5AspectsOfCKEditor5Plugin.php
CKEditor5Plugin.php in core/modules/ckeditor5/src/Attribute/CKEditor5Plugin.php
Condition.php in core/lib/Drupal/Core/Condition/Attribute/Condition.php
ConfigAction.php in core/lib/Drupal/Core/Config/Action/Attribute/ConfigAction.php
Constraint.php in core/lib/Drupal/Core/Validation/Attribute/Constraint.php
CustomPlugin.php in core/tests/Drupal/Tests/Component/Plugin/Attribute/Fixtures/CustomPlugin.php
DataType.php in core/lib/Drupal/Core/TypedData/Attribute/DataType.php
DisplayVariant.php in core/lib/Drupal/Core/Display/Attribute/DisplayVariant.php
DrupalAspectsOfCKEditor5Plugin.php in core/modules/ckeditor5/src/Attribute/DrupalAspectsOfCKEditor5Plugin.php
Editor.php in core/modules/editor/src/Attribute/Editor.php
EntityReferenceSelection.php in core/lib/Drupal/Core/Entity/Attribute/EntityReferenceSelection.php
FieldFormatter.php in core/lib/Drupal/Core/Field/Attribute/FieldFormatter.php
FieldType.php in core/lib/Drupal/Core/Field/Attribute/FieldType.php
FieldWidget.php in core/lib/Drupal/Core/Field/Attribute/FieldWidget.php
Filter.php in core/modules/filter/src/Attribute/Filter.php
HelpSection.php in core/modules/help/src/Attribute/HelpSection.php
ImageEffect.php in core/modules/image/src/Attribute/ImageEffect.php
ImageToolkit.php in core/lib/Drupal/Core/ImageToolkit/Attribute/ImageToolkit.php
ImageToolkitOperation.php in core/lib/Drupal/Core/ImageToolkit/Attribute/ImageToolkitOperation.php
LanguageNegotiation.php in core/modules/language/src/Attribute/LanguageNegotiation.php
Layout.php in core/lib/Drupal/Core/Layout/Attribute/Layout.php
Mail.php in core/lib/Drupal/Core/Mail/Attribute/Mail.php
MediaSource.php in core/modules/media/src/Attribute/MediaSource.php
MigrateDestination.php in core/modules/migrate/src/Attribute/MigrateDestination.php
MigrateField.php in core/modules/migrate_drupal/src/Attribute/MigrateField.php
MigrateProcess.php in core/modules/migrate/src/Attribute/MigrateProcess.php
PluginExample.php in core/modules/system/tests/modules/plugin_test/src/Plugin/Attribute/PluginExample.php
PluginTest.php in core/tests/Drupal/Tests/Component/Plugin/Attribute/PluginTest.php
QueueWorker.php in core/lib/Drupal/Core/Queue/Attribute/QueueWorker.php
RenderElement.php in core/lib/Drupal/Core/Render/Attribute/RenderElement.php
RestResource.php in core/modules/rest/src/Attribute/RestResource.php
Search.php in core/modules/search/src/Attribute/Search.php
SectionStorage.php in core/modules/layout_builder/src/Attribute/SectionStorage.php
ViewsAccess.php in core/modules/views/src/Attribute/ViewsAccess.php
ViewsArgument.php in core/modules/views/src/Attribute/ViewsArgument.php
ViewsArgumentDefault.php in core/modules/views/src/Attribute/ViewsArgumentDefault.php
ViewsArgumentValidator.php in core/modules/views/src/Attribute/ViewsArgumentValidator.php
ViewsCache.php in core/modules/views/src/Attribute/ViewsCache.php
ViewsDisplay.php in core/modules/views/src/Attribute/ViewsDisplay.php
ViewsDisplayExtender.php in core/modules/views/src/Attribute/ViewsDisplayExtender.php
ViewsExposedForm.php in core/modules/views/src/Attribute/ViewsExposedForm.php
ViewsHandlerManager.php in core/modules/views/src/Plugin/ViewsHandlerManager.php
ViewsPager.php in core/modules/views/src/Attribute/ViewsPager.php
ViewsPluginManager.php in core/modules/views/src/Plugin/ViewsPluginManager.php
ViewsQuery.php in core/modules/views/src/Attribute/ViewsQuery.php
ViewsRow.php in core/modules/views/src/Attribute/ViewsRow.php
ViewsStyle.php in core/modules/views/src/Attribute/ViewsStyle.php
ViewsWizard.php in core/modules/views/src/Attribute/ViewsWizard.php
WorkflowType.php in core/modules/workflows/src/Attribute/WorkflowType.php

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