16 files declare their use of LinkItemInterface

LinkFieldTest.php in core/modules/link/tests/src/Functional/LinkFieldTest.php
LinkFieldUITest.php in core/modules/link/tests/src/Functional/LinkFieldUITest.php
LinkFormatter.php in core/modules/link/src/Plugin/Field/FieldFormatter/LinkFormatter.php
LinkFormatterTest.php in core/modules/link/tests/src/Unit/LinkFormatterTest.php
LinkItem.php in core/modules/link/src/Plugin/Field/FieldType/LinkItem.php
LinkItemSerializationTest.php in core/modules/link/tests/src/Kernel/LinkItemSerializationTest.php
LinkItemTest.php in core/modules/link/tests/src/Kernel/LinkItemTest.php
LinkNotExistingInternalConstraintValidatorTest.php in core/modules/link/tests/src/Unit/Plugin/Validation/Constraint/LinkNotExistingInternalConstraintValidatorTest.php
LinkTestBaseFieldHooks.php in core/modules/link/tests/modules/link_test_base_field/src/Hook/LinkTestBaseFieldHooks.php
LinkTypeConstraintValidator.php in core/modules/link/src/Plugin/Validation/Constraint/LinkTypeConstraintValidator.php
LinkWidget.php in core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
link_test_base_field.module in core/modules/link/tests/modules/link_test_base_field/link_test_base_field.module
MenuLinkContent.php in core/modules/menu_link_content/src/Entity/MenuLinkContent.php
MigrateFieldInstanceTest.php in core/modules/field/tests/src/Kernel/Migrate/d6/MigrateFieldInstanceTest.php
RouteCachingLanguageTest.php in core/tests/Drupal/FunctionalTests/Routing/RouteCachingLanguageTest.php
Shortcut.php in core/modules/shortcut/src/Entity/Shortcut.php

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