32 files declare their use of FileInterface in Drupal 8

claro.theme in core/themes/claro/claro.theme

Functions to support theming in the Claro theme.

ComputedFileUrlTest.php in core/modules/file/tests/src/Kernel/ComputedFileUrlTest.php

DatabaseFileUsageBackend.php in core/modules/file/src/FileUsage/DatabaseFileUsageBackend.php

EditorFileReference.php in core/modules/editor/src/Plugin/Filter/EditorFileReference.php

editor_test.module in core/modules/editor/tests/modules/editor_test.module

Helper module for the Text Editor tests.

file.module in core/modules/file/file.module

Defines a "managed_file" Form API field and a "file" field for Field module.

File.php in core/modules/file/src/Entity/File.php

File.php in core/modules/media/src/Plugin/media/Source/File.php

FileEntityNormalizer.php in core/modules/hal/src/Normalizer/FileEntityNormalizer.php

FileFieldTestBase.php in core/modules/file/src/Tests/FileFieldTestBase.php

FileFieldTestBase.php in core/modules/file/tests/src/Functional/FileFieldTestBase.php

FileFieldTestBaseTrait.php in core/tests/Drupal/TestTools/PhpUnitCompatibility/PhpUnit6/FileFieldTestBaseTrait.php

FileLegacyTest.php in core/modules/file/tests/src/Kernel/FileLegacyTest.php

FileManagedTestBase.php in core/modules/file/src/Tests/FileManagedTestBase.php

FileManagedTestBase.php in core/modules/file/tests/src/Functional/FileManagedTestBase.php

FileManagedUnitTestBase.php in core/modules/file/tests/src/Kernel/FileManagedUnitTestBase.php

FileMigrationSetupTrait.php in core/modules/file/tests/src/Kernel/Migrate/d7/FileMigrationSetupTrait.php

FileUploadForm.php in core/modules/media_library/src/Form/FileUploadForm.php

FileUploadResource.php in core/modules/file/src/Plugin/rest/resource/FileUploadResource.php

FileUsageBase.php in core/modules/file/src/FileUsage/FileUsageBase.php

FileUsageInterface.php in core/modules/file/src/FileUsage/FileUsageInterface.php

image.module in core/modules/image/image.module

Exposes global functionality for creating image styles.

InlineBlockPrivateFilesTest.php in core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockPrivateFilesTest.php

LegacyFileTest.php in core/modules/file/tests/src/Unit/LegacyFileTest.php

LoadTest.php in core/modules/file/tests/src/Kernel/LoadTest.php

locale.bulk.inc in core/modules/locale/locale.bulk.inc

Mass import-export and batch import functionality for Gettext .po files.

MigrateFileTest.php in core/modules/file/tests/src/Kernel/Migrate/d6/MigrateFileTest.php

MigrateUserPictureD6FileTest.php in core/modules/user/tests/src/Kernel/Migrate/d6/MigrateUserPictureD6FileTest.php

ResponsiveImageFormatter.php in core/modules/responsive_image/src/Plugin/Field/FieldFormatter/ResponsiveImageFormatter.php

TemporaryJsonapiFileFieldUploader.php in core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php

TestFileUsage.php in core/modules/system/tests/modules/service_provider_test/src/TestFileUsage.php

UrlPlainFormatter.php in core/modules/file/src/Plugin/Field/FieldFormatter/UrlPlainFormatter.php