BlockPluginInterface.php in core/lib/Drupal/Core/Block/BlockPluginInterface.php
HelpTopicPluginInterface.php in core/modules/help/src/HelpTopicPluginInterface.php
LayoutBuilderEntityViewDisplay.php in core/modules/layout_builder/src/Entity/LayoutBuilderEntityViewDisplay.php
LayoutEntityHelperTrait.php in core/modules/layout_builder/src/LayoutEntityHelperTrait.php
LayoutEntityHelperTraitTest.php in core/modules/layout_builder/tests/src/Unit/LayoutEntityHelperTraitTest.php
LayoutInterface.php in core/lib/Drupal/Core/Layout/LayoutInterface.php
media.module in core/modules/media/media.module
Provides media items.
MigrationInterface.php in core/modules/migrate/src/Plugin/MigrationInterface.php
ViewsPluginInterface.php in core/modules/views/src/Plugin/views/ViewsPluginInterface.php
WorkflowTypeInterface.php in core/modules/workflows/src/WorkflowTypeInterface.php