9 files declare their use of RestResourceConfig in Drupal 9

ConfigDependenciesTest.php in core/modules/rest/tests/src/Kernel/Entity/ConfigDependenciesTest.php

ContentModerationStateResourceTest.php in core/modules/content_moderation/tests/src/Kernel/ContentModerationStateResourceTest.php

ResourceTest.php in core/modules/rest/tests/src/Functional/ResourceTest.php

ResponseGeneratorTest.php in core/modules/system/tests/src/Functional/System/ResponseGeneratorTest.php

RestPermissionsTest.php in core/modules/rest/tests/src/Kernel/Entity/RestPermissionsTest.php

RestResourceConfigResourceTestBase.php in core/modules/rest/tests/src/Functional/Rest/RestResourceConfigResourceTestBase.php

RestResourceConfigTest.php in core/modules/jsonapi/tests/src/Functional/RestResourceConfigTest.php

RestResourceConfigTest.php in core/modules/rest/tests/src/Unit/Entity/RestResourceConfigTest.php

RestResourceConfigTest.php in core/modules/rest/tests/src/Kernel/Entity/RestResourceConfigTest.php