6 files declare their use of FileUploadSanitizeNameEvent in Drupal 9

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

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

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

FileUploadSanitizeNameEventTest.php in core/tests/Drupal/Tests/Core/File/FileUploadSanitizeNameEventTest.php

SecurityFileUploadEventSubscriber.php in core/modules/system/src/EventSubscriber/SecurityFileUploadEventSubscriber.php

SecurityFileUploadEventSubscriberTest.php in core/modules/system/tests/src/Unit/Event/SecurityFileUploadEventSubscriberTest.php

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