6 files declare their use of PluginAwareInterface in Drupal 9

PluginFormBase.php in core/lib/Drupal/Core/Plugin/PluginFormBase.php

PluginFormFactory.php in core/lib/Drupal/Core/Plugin/PluginFormFactory.php

PluginFormFactoryTest.php in core/tests/Drupal/Tests/Core/Plugin/PluginFormFactoryTest.php

WorkflowTypeConfigureFormBase.php in core/modules/workflows/src/Plugin/WorkflowTypeConfigureFormBase.php

WorkflowTypeStateFormBase.php in core/modules/workflows/src/Plugin/WorkflowTypeStateFormBase.php

WorkflowTypeTransitionFormBase.php in core/modules/workflows/src/Plugin/WorkflowTypeTransitionFormBase.php