15 files declare their use of LinkManager in JSON:API 8

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

EntityNormalizer.php in src/Normalizer/EntityNormalizer.php

EntityNormalizerValueTest.php in tests/src/Unit/Normalizer/Value/EntityNormalizerValueTest.php

EntityReferenceFieldNormalizer.php in src/Normalizer/EntityReferenceFieldNormalizer.php

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

EntityResource.php in src/Controller/EntityResource.php

EntityToJsonApiTest.php in tests/src/Kernel/EntityToJsonApiTest.php

JsonApiDocumentTopLevelNormalizer.php in src/Normalizer/JsonApiDocumentTopLevelNormalizer.php

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

JsonApiDocumentTopLevelNormalizerTest.php in tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php

JsonApiDocumentTopLevelNormalizerValueTest.php in tests/src/Unit/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValueTest.php

LinkManagerTest.php in tests/src/Unit/LinkManager/LinkManagerTest.php

RelationshipNormalizer.php in src/Normalizer/RelationshipNormalizer.php

RelationshipNormalizerValueTest.php in tests/src/Unit/Normalizer/Value/RelationshipNormalizerValueTest.php

RequestHandler.php in src/Controller/RequestHandler.php