73 files declare their use of FieldItemListInterface

AuthorFormatter.php in core/modules/user/src/Plugin/Field/FieldFormatter/AuthorFormatter.php
AuthorNameFormatter.php in core/modules/comment/src/Plugin/Field/FieldFormatter/AuthorNameFormatter.php
BasicStringFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/BasicStringFormatter.php
BooleanCheckboxWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/BooleanCheckboxWidget.php
BooleanFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/BooleanFormatter.php
CommentAccessControlHandler.php in core/modules/comment/src/CommentAccessControlHandler.php
CommentDefaultFormatter.php in core/modules/comment/src/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
CommentItemTest.php in core/modules/comment/tests/src/Kernel/CommentItemTest.php
CommentWidget.php in core/modules/comment/src/Plugin/Field/FieldWidget/CommentWidget.php
DateRangeCustomFormatter.php in core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangeCustomFormatter.php
DateRangeDatelistWidget.php in core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
DateRangeDefaultWidget.php in core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeDefaultWidget.php
DateRangePlainFormatter.php in core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangePlainFormatter.php
DateRangeWidgetBase.php in core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
DateTimeCustomFormatter.php in core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php
DateTimeDatelistWidget.php in core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
DateTimeDefaultWidget.php in core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDefaultWidget.php
DateTimeFormatterBase.php in core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeFormatterBase.php
DateTimeItemTest.php in core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
DateTimePlainFormatter.php in core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php
DateTimeRangeTrait.php in core/modules/datetime_range/src/DateTimeRangeTrait.php
DateTimeTimeAgoFormatter.php in core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeTimeAgoFormatter.php
DateTimeWidgetBase.php in core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php
DummyAjaxFormatter.php in core/modules/image/tests/modules/image_module_test/src/Plugin/Field/FieldFormatter/DummyAjaxFormatter.php
DummyAjaxWidget.php in core/modules/image/tests/modules/image_module_test/src/Plugin/Field/FieldWidget/DummyAjaxWidget.php
DummyImageFormatter.php in core/modules/image/tests/modules/image_module_test/src/Plugin/Field/FieldFormatter/DummyImageFormatter.php
EmailDefaultWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EmailDefaultWidget.php
EntityAccessControlHandler.php in core/lib/Drupal/Core/Entity/EntityAccessControlHandler.php
EntityAccessControlHandlerInterface.php in core/lib/Drupal/Core/Entity/EntityAccessControlHandlerInterface.php
EntityFieldTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityFieldTest.php
EntityReferenceAutocompleteTagsWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteTagsWidget.php
EntityReferenceAutocompleteWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteWidget.php
EntityReferenceEntityFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php
EntityReferenceFormatterBase.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php
EntityReferenceIdFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceIdFormatter.php
EntityReferenceLabelFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php
EntityReferenceTaxonomyTermRssFormatter.php in core/modules/taxonomy/src/Plugin/Field/FieldFormatter/EntityReferenceTaxonomyTermRssFormatter.php
EntityTestReferenceCustomCacheTagFormatter.php in core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldFormatter/EntityTestReferenceCustomCacheTagFormatter.php
EntityViewBuilder.php in core/lib/Drupal/Core/Entity/EntityViewBuilder.php
EntityViewBuilderInterface.php in core/lib/Drupal/Core/Entity/EntityViewBuilderInterface.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.
ImageFormatter.php in core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatter.php
ImageItemTest.php in core/modules/image/tests/src/Kernel/ImageItemTest.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
LanguageSelectWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/LanguageSelectWidget.php
MailToFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/MailToFormatter.php
NumberWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/NumberWidget.php
NumericFormatterBase.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/NumericFormatterBase.php
NumericUnformattedFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/NumericUnformattedFormatter.php
OptionsButtonsWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsButtonsWidget.php
OptionsSelectWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsSelectWidget.php
OptionsWidgetBase.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/OptionsWidgetBase.php
PathWidget.php in core/modules/path/src/Plugin/Field/FieldWidget/PathWidget.php
ShapeOnlyColorEditableWidget.php in core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldWidget/ShapeOnlyColorEditableWidget.php
StringFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/StringFormatter.php
StringTextareaWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringTextareaWidget.php
StringTextfieldWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringTextfieldWidget.php
TextareaWidget.php in core/modules/text/src/Plugin/Field/FieldWidget/TextareaWidget.php
TextareaWithSummaryWidget.php in core/modules/text/src/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php
TextDefaultFormatter.php in core/modules/text/src/Plugin/Field/FieldFormatter/TextDefaultFormatter.php
TextfieldWidget.php in core/modules/text/src/Plugin/Field/FieldWidget/TextfieldWidget.php
TextTrimmedFormatter.php in core/modules/text/src/Plugin/Field/FieldFormatter/TextTrimmedFormatter.php
TextWithSummaryItemTest.php in core/modules/text/tests/src/Kernel/TextWithSummaryItemTest.php
TimestampAgoFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/TimestampAgoFormatter.php
TimestampDatetimeWidget.php in core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php
TimestampFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/TimestampFormatter.php
UriLinkFormatter.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/UriLinkFormatter.php
UriWidget.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/UriWidget.php
UserAccessControlHandler.php in core/modules/user/src/UserAccessControlHandler.php
UserMailRequiredValidatorTest.php in core/modules/user/tests/src/Unit/Plugin/Validation/Constraint/UserMailRequiredValidatorTest.php
UserNameConstraintValidator.php in core/modules/user/src/Plugin/Validation/Constraint/UserNameConstraintValidator.php
UserNameFormatter.php in core/modules/user/src/Plugin/Field/FieldFormatter/UserNameFormatter.php

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