8 files declare their use of JsonApiDocumentTopLevel in JSON:API 8
- EntityResource.php in src/Controller/ EntityResource.php 
- EntityResourceTest.php in tests/src/ Kernel/ Controller/ EntityResourceTest.php 
- EntityToJsonApi.php in src/EntityToJsonApi.php 
- JsonApiDocumentTopLevelNormalizer.php in src/Normalizer/ JsonApiDocumentTopLevelNormalizer.php 
- JsonApiDocumentTopLevelNormalizerTest.php in tests/src/ Kernel/ Normalizer/ JsonApiDocumentTopLevelNormalizerTest.php 
- RelationshipItemNormalizer.php in src/Normalizer/ RelationshipItemNormalizer.php 
- ResourceTestBase.php in tests/src/ Functional/ ResourceTestBase.php 
- Routes.php in src/Routing/ Routes.php 
