9 files declare their use of ActionMethod

ConfigEntityBase.php in core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
ConfigTest.php in core/modules/config/tests/config_test/src/Entity/ConfigTest.php
DuplicatePluralizedMethodName.php in core/modules/config/tests/config_test/src/ConfigActionErrorEntity/DuplicatePluralizedMethodName.php
DuplicatePluralizedOtherMethodName.php in core/modules/config/tests/config_test/src/ConfigActionErrorEntity/DuplicatePluralizedOtherMethodName.php
EntityDisplayBase.php in core/lib/Drupal/Core/Entity/EntityDisplayBase.php
EntityMethodDeriver.php in core/lib/Drupal/Core/Config/Action/Plugin/ConfigAction/Deriver/EntityMethodDeriver.php
FieldConfigBase.php in core/lib/Drupal/Core/Field/FieldConfigBase.php
FilterFormat.php in core/modules/filter/src/Entity/FilterFormat.php
Role.php in core/modules/user/src/Entity/Role.php

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