12 files declare their use of Bytes

ByteSizeMarkup.php in core/lib/Drupal/Core/StringTranslation/ByteSizeMarkup.php
ByteSizeMarkupTest.php in core/tests/Drupal/Tests/Core/StringTranslation/ByteSizeMarkupTest.php
BytesTest.php in core/tests/Drupal/Tests/Component/Utility/BytesTest.php
CKEditor5ImageController.php in core/modules/ckeditor5/src/Controller/CKEditor5ImageController.php
EditorImageDialog.php in core/modules/editor/src/Form/EditorImageDialog.php
FileItem.php in core/modules/file/src/Plugin/Field/FieldType/FileItem.php
FileValidationConstraintValidator.php in core/modules/file/src/Plugin/Validation/Constraint/FileValidationConstraintValidator.php
FileValidatorSettingsTrait.php in core/modules/file/src/Validation/FileValidatorSettingsTrait.php
MaximumFileSizeExceededUploadTest.php in core/modules/file/tests/src/FunctionalJavascript/MaximumFileSizeExceededUploadTest.php
MigrateExecutable.php in core/modules/migrate/src/MigrateExecutable.php
StatusTest.php in core/modules/system/tests/src/Functional/System/StatusTest.php
system.install in core/modules/system/system.install
Install, update and uninstall functions for the system module.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.