20 files declare their use of Regions in Facebook Instant Articles 8.2

AdFormatter.php in src/Plugin/Field/FieldFormatter/AdFormatter.php

AdFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/AdFormatterTest.php

AnalyticsFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/AnalyticsFormatterTest.php

AuthorFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/AuthorFormatterTest.php

AuthorReferenceFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/AuthorReferenceFormatterTest.php

CopyrightFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/CopyrightFormatterTest.php

CreditsFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/CreditsFormatterTest.php

EntityViewDisplayEditForm.php in src/Form/EntityViewDisplayEditForm.php

FieldItemListNormalizer.php in src/Normalizer/FieldItemListNormalizer.php

ImageFormatter.php in src/Plugin/Field/FieldFormatter/ImageFormatter.php

ImageFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/ImageFormatterTest.php

InteractiveFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/InteractiveFormatterTest.php

KickerFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/KickerFormatterTest.php

ListFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/ListFormatterTest.php

ParagraphFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/ParagraphFormatterTest.php

SimpleBlockFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/SimpleBlockFormatterTest.php

SubtitleFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/SubtitleFormatterTest.php

TransformerFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/TransformerFormatterTest.php

VideoFormatter.php in src/Plugin/Field/FieldFormatter/VideoFormatter.php

VideoFormatterTest.php in tests/src/Kernel/Plugin/Field/FieldFormatter/VideoFormatterTest.php