9 files declare their use of PluginManagerInterface

ActionBag.php in drupal/core/lib/Drupal/Core/Action/ActionBag.php
Contains \Drupal\Core\Action\ActionBag.
BlockPluginBag.php in drupal/core/modules/block/lib/Drupal/block/BlockPluginBag.php
Contains \Drupal\block\BlockPluginBag.
DisplayBag.php in drupal/core/modules/views/lib/Drupal/views/DisplayBag.php
Contains \Drupal\views\DisplayBag.
EditorSelector.php in drupal/core/modules/edit/lib/Drupal/edit/EditorSelector.php
Contains \Drupal\edit\EditorSelector.
ExecutableManagerInterface.php in drupal/core/lib/Drupal/Core/Executable/ExecutableManagerInterface.php
Contains \Drupal\Core\Executable\ExecutableManagerInterface.
FilterBag.php in drupal/core/modules/filter/lib/Drupal/filter/FilterBag.php
Contains \Drupal\filter\FilterBag.
MetadataGenerator.php in drupal/core/modules/edit/lib/Drupal/edit/MetadataGenerator.php
Contains \Drupal\edit\MetadataGenerator.
TestPluginBag.php in drupal/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/TestPluginBag.php
Contains \Drupal\plugin_test\Plugin\TestPluginBag.
TipsBag.php in drupal/core/modules/tour/lib/Drupal/tour/TipsBag.php
Contains \Drupal\tour\TipsBag.