21 files declare their use of ContextAwarePluginInterface

BlockAccessControlHandler.php in core/modules/block/src/BlockAccessControlHandler.php
BlockBase.php in core/lib/Drupal/Core/Block/BlockBase.php
BlockForm.php in core/modules/block/src/BlockForm.php
BlockViewBuilder.php in core/modules/block/src/BlockViewBuilder.php
ConfigureBlockFormBase.php in core/modules/layout_builder/src/Form/ConfigureBlockFormBase.php
ConfigureSectionForm.php in core/modules/layout_builder/src/Form/ConfigureSectionForm.php
ContextAwarePluginTraitTest.php in core/tests/Drupal/KernelTests/Core/Plugin/Context/ContextAwarePluginTraitTest.php
ContextHandler.php in core/lib/Drupal/Core/Plugin/Context/ContextHandler.php
ContextHandlerInterface.php in core/lib/Drupal/Core/Plugin/Context/ContextHandlerInterface.php
ContextHandlerTest.php in core/tests/Drupal/KernelTests/Core/Plugin/ContextHandlerTest.php
ContextHandlerTest.php in core/tests/Drupal/Tests/Core/Plugin/ContextHandlerTest.php
Contains \Drupal\Tests\Core\Plugin\ContextHandlerTest.
ExecutablePluginBase.php in core/lib/Drupal/Core/Executable/ExecutablePluginBase.php
ExtraFieldBlock.php in core/modules/layout_builder/src/Plugin/Block/ExtraFieldBlock.php
FieldBlock.php in core/modules/layout_builder/src/Plugin/Block/FieldBlock.php
LayoutInterface.php in core/lib/Drupal/Core/Layout/LayoutInterface.php
MockComplexContextBlock.php in core/modules/system/tests/modules/plugin_test/src/Plugin/plugin_test/mock_block/MockComplexContextBlock.php
MockUserNameBlock.php in core/modules/system/tests/modules/plugin_test/src/Plugin/plugin_test/mock_block/MockUserNameBlock.php
SectionComponent.php in core/modules/layout_builder/src/SectionComponent.php
SectionRenderTest.php in core/modules/layout_builder/tests/src/Unit/SectionRenderTest.php
SectionStorageInterface.php in core/modules/layout_builder/src/SectionStorageInterface.php
TypedDataStringBlock.php in core/modules/system/tests/modules/plugin_test/src/Plugin/plugin_test/mock_block/TypedDataStringBlock.php

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.