6 files declare their use of ResourceIdentifier in JSON:API 8.2

EntityAccessDeniedHttpException.php in src/Exception/EntityAccessDeniedHttpException.php

EntityReferenceFieldNormalizer.php in src/Normalizer/EntityReferenceFieldNormalizer.php

EntityResource.php in src/Controller/EntityResource.php

EntityResourceTest.php in tests/src/Kernel/Controller/EntityResourceTest.php

ResourceIdentifierNormalizer.php in src/Normalizer/ResourceIdentifierNormalizer.php

ResourceIdentifierNormalizerTest.php in tests/src/Unit/Normalizer/ResourceIdentifierNormalizerTest.php