6 files declare their use of CategorizingPluginManagerTrait

ActionManager.php in core/lib/Drupal/Core/Action/ActionManager.php
BlockManager.php in core/lib/Drupal/Core/Block/BlockManager.php
CategorizingPluginManagerTraitTest.php in core/tests/Drupal/Tests/Core/Plugin/CategorizingPluginManagerTraitTest.php
ComponentPluginManager.php in core/lib/Drupal/Core/Theme/ComponentPluginManager.php
ConditionManager.php in core/lib/Drupal/Core/Condition/ConditionManager.php
FieldTypePluginManager.php in core/lib/Drupal/Core/Field/FieldTypePluginManager.php

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