27 files declare their use of DependentPluginInterface

ArgumentPluginBase.php in core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php
BlockPluginInterface.php in core/lib/Drupal/Core/Block/BlockPluginInterface.php
ConditionInterface.php in core/lib/Drupal/Core/Condition/ConditionInterface.php
Config.php in core/modules/migrate/src/Plugin/migrate/destination/Config.php
ConfigurableActionBase.php in core/lib/Drupal/Core/Action/ConfigurableActionBase.php
ConfigurableSearchPluginInterface.php in core/modules/search/src/Plugin/ConfigurableSearchPluginInterface.php
ContextHandlerTest.php in core/tests/Drupal/Tests/Core/Plugin/ContextHandlerTest.php
DisplayPluginBase.php in core/modules/views/src/Plugin/views/display/DisplayPluginBase.php
DrupalSqlBase.php in core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php
EmptySource.php in core/modules/migrate_drupal/src/Plugin/migrate/source/EmptySource.php
Entity.php in core/modules/migrate/src/Plugin/migrate/destination/Entity.php
EntityActionBase.php in core/lib/Drupal/Core/Action/Plugin/Action/EntityActionBase.php
EntityField.php in core/modules/views/src/Plugin/views/field/EntityField.php
EntityResource.php in core/modules/rest/src/Plugin/rest/resource/EntityResource.php
FilterInterface.php in core/modules/filter/src/Plugin/FilterInterface.php
ImageEffectInterface.php in core/modules/image/src/ImageEffectInterface.php
LayoutInterface.php in core/lib/Drupal/Core/Layout/LayoutInterface.php
LayoutTestDependenciesPlugin.php in core/modules/system/tests/modules/layout_test/src/Plugin/Layout/LayoutTestDependenciesPlugin.php
MediaSourceInterface.php in core/modules/media/src/MediaSourceInterface.php
PluginBase.php in core/modules/views/src/Plugin/views/PluginBase.php
PluginDependencyTrait.php in core/lib/Drupal/Core/Plugin/PluginDependencyTrait.php
PluginDependencyTraitTest.php in core/tests/Drupal/Tests/Core/Plugin/PluginDependencyTraitTest.php
PluginSettingsBase.php in core/lib/Drupal/Core/Field/PluginSettingsBase.php
SelectionPluginBase.php in core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginBase.php
TestConfigurablePlugin.php in core/tests/Drupal/Tests/Core/Plugin/Fixtures/TestConfigurablePlugin.php
VariantInterface.php in core/lib/Drupal/Core/Display/VariantInterface.php
WorkflowTypeInterface.php in core/modules/workflows/src/WorkflowTypeInterface.php

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