11 files declare their use of Serializer in Zircon Profile 8

ComplexDataNormalizerTest.php in core/modules/serialization/tests/src/Unit/Normalizer/ComplexDataNormalizerTest.php

Contains \Drupal\Tests\serialization\Unit\Normalizer\ComplexDataNormalizerTest.

CustomNormalizerTest.php in vendor/symfony/serializer/Tests/Normalizer/CustomNormalizerTest.php

EntityReferenceFieldItemNormalizerTest.php in core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php

Contains \Drupal\Tests\serialization\Unit\Normalizer\EntityReferenceFieldItemNormalizerTest.

FileNormalizeTest.php in core/modules/hal/src/Tests/FileNormalizeTest.php

Contains \Drupal\hal\Tests\FileNormalizeTest.

GetSetMethodNormalizerTest.php in vendor/symfony/serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php

JsonEncoderTest.php in vendor/symfony/serializer/Tests/Encoder/JsonEncoderTest.php

NormalizerTestBase.php in core/modules/hal/src/Tests/NormalizerTestBase.php

Contains \Drupal\hal\Tests\NormalizerTestBase.

ObjectNormalizerTest.php in vendor/symfony/serializer/Tests/Normalizer/ObjectNormalizerTest.php

PropertyNormalizerTest.php in vendor/symfony/serializer/Tests/Normalizer/PropertyNormalizerTest.php

SerializerTest.php in vendor/symfony/serializer/Tests/SerializerTest.php

XmlEncoderTest.php in vendor/symfony/serializer/Tests/Encoder/XmlEncoderTest.php