75 files declare their use of FieldDefinitionInterface

AuthorFormatter.php in core/modules/user/src/Plugin/Field/FieldFormatter/AuthorFormatter.php
AuthorNameFormatter.php in core/modules/comment/src/Plugin/Field/FieldFormatter/AuthorNameFormatter.php
BooleanItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/BooleanItem.php
CommentAccessControlHandler.php in core/modules/comment/src/CommentAccessControlHandler.php
CommentDefaultFormatter.php in core/modules/comment/src/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
CommentItem.php in core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php
CommentPermalinkFormatter.php in core/modules/comment/src/Plugin/Field/FieldFormatter/CommentPermalinkFormatter.php
ContentEntityNullStorage.php in core/lib/Drupal/Core/Entity/ContentEntityNullStorage.php
ContentEntityStorageBase.php in core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
ContentTranslationSynchronizedFieldsConstraintValidator.php in core/modules/content_translation/src/Plugin/Validation/Constraint/ContentTranslationSynchronizedFieldsConstraintValidator.php
content_translation.admin.inc in core/modules/content_translation/content_translation.admin.inc
The content translation administration forms.
DateRangeDefaultWidget.php in core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php
DateRangeFieldItemList.php in core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeFieldItemList.php
DateRangeItem.php in core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php
DateTimeDefaultWidget.php in core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php
DateTimeFieldItemList.php in core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php
DateTimeFormatterBase.php in core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeFormatterBase.php
DateTimeItem.php in core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php
DecimalItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/DecimalItem.php
editor.module in core/modules/editor/editor.module
Adds bindings for client-side "text editors" to text formats.
EmailItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EmailItem.php
EntityAccessControlHandler.php in core/lib/Drupal/Core/Entity/EntityAccessControlHandler.php
EntityAccessControlHandlerInterface.php in core/lib/Drupal/Core/Entity/EntityAccessControlHandlerInterface.php
EntityDisplayBase.php in core/lib/Drupal/Core/Entity/EntityDisplayBase.php
EntityDisplayFormBase.php in core/modules/field_ui/src/Form/EntityDisplayFormBase.php
EntityFieldManagerTest.php in core/tests/Drupal/Tests/Core/Entity/EntityFieldManagerTest.php
EntityFieldTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityFieldTest.php
EntityFormDisplayEditForm.php in core/modules/field_ui/src/Form/EntityFormDisplayEditForm.php
EntityReferenceEntityFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php
EntityReferenceItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
EntityReferenceItemInterface.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItemInterface.php
EntityReferenceTaxonomyTermRssFormatter.php in core/modules/taxonomy/src/Plugin/Field/FieldFormatter/EntityReferenceTaxonomyTermRssFormatter.php
EntityTypedDataDefinitionTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityTypedDataDefinitionTest.php
EntityViewDisplayEditForm.php in core/modules/field_ui/src/Form/EntityViewDisplayEditForm.php
entity_test.module in core/modules/system/tests/modules/entity_test/entity_test.module
Test module for the entity API providing several entity types for testing.
FieldableEntityStorageInterface.php in core/lib/Drupal/Core/Entity/FieldableEntityStorageInterface.php
FieldDefinitionListenerTest.php in core/tests/Drupal/Tests/Core/Field/FieldDefinitionListenerTest.php
FieldItemListTest.php in core/tests/Drupal/Tests/Core/Field/FieldItemListTest.php
FieldLayoutBuilder.php in core/modules/field_layout/src/FieldLayoutBuilder.php
FieldLayoutBuilderTest.php in core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php
FieldTranslationSynchronizer.php in core/modules/content_translation/src/FieldTranslationSynchronizer.php
FieldTranslationSynchronizerInterface.php in core/modules/content_translation/src/FieldTranslationSynchronizerInterface.php
FileUploadLocationTrait.php in core/modules/file/src/Upload/FileUploadLocationTrait.php
FloatItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/FloatItem.php
ImageFormatter.php in core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatter.php
ImageItem.php in core/modules/image/src/Plugin/Field/FieldType/ImageItem.php
ImageUrlFormatter.php in core/modules/image/src/Plugin/Field/FieldFormatter/ImageUrlFormatter.php
ImageWidget.php in core/modules/image/src/Plugin/Field/FieldWidget/ImageWidget.php
IntegerItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/IntegerItem.php
LanguageFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/LanguageFormatter.php
LanguageItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/LanguageItem.php
OptionsWidgetBase.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php
PathItem.php in core/modules/path/src/Plugin/Field/FieldType/PathItem.php
SelectionPluginManager.php in core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginManager.php
SelectionPluginManagerInterface.php in core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginManagerInterface.php
SqlContentEntityStorage.php in core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php
StatusItem.php in core/modules/user/src/StatusItem.php
StringFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/StringFormatter.php
StringItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
StringItemTest.php in core/tests/Drupal/Tests/Core/Field/StringItemTest.php
StringLongItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringLongItem.php
TestBaseFieldDefinitionInterface.php in core/tests/Drupal/Tests/Core/Field/TestBaseFieldDefinitionInterface.php
TextItemBase.php in core/modules/text/src/Plugin/Field/FieldType/TextItemBase.php
TimestampAgoFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/TimestampAgoFormatter.php
TimestampFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/TimestampFormatter.php
TimestampItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/TimestampItem.php
TimeZoneItem.php in core/modules/user/src/TimeZoneItem.php
UriItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UriItem.php
UriItemTest.php in core/tests/Drupal/Tests/Core/Field/UriItemTest.php
UserAccessControlHandler.php in core/modules/user/src/UserAccessControlHandler.php
UserMailRequiredValidatorTest.php in core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/UserMailRequiredValidatorTest.php
UserNameFormatter.php in core/modules/user/src/Plugin/Field/FieldFormatter/UserNameFormatter.php
UserNameItem.php in core/modules/user/src/UserNameItem.php
UserNameItemTest.php in core/modules/user/tests/src/Unit/UserNameItemTest.php
UuidItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UuidItem.php

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