# extendedAttributes The extended file attributes synced by the File Provider extension. ``` optional var extendedAttributes: [String : Data] { get } ``` ## Discussion The extended file attributes are part of the item’s metadata. The system sets extended attributes on dataless files, and preserves them on files that it renders dataless. The system decides which attributes to sync. To sync an attribute, it calls the `xattr_name_with_flags(_:_:)` method and passes the `XATTR_FLAG_SYNCABLE` flag. Some older attributes are also synced. The system caps the syncable extended attributes to about 32KiB total for each item. If the extended attributes exceed this limit, the system automatically makes some of the attributes nonsyncable. The system also decides which nonsyncable attributes it preserves on the local copy when a remote item changes. For example, it preserves attributes created by calling `xattr_name_with_flags(_:_:)` and passing `XATTR_FLAG_CONTENT_DEPENDENT` as long as the remote change didn’t modify the [`contentVersion`](/documentation/FileProvider/NSFileProviderItemVersion/contentVersion) property for the item’s version. This dictionary doesn’t list extended attributes that are already covered by [`NSFileProviderItemFields`](/documentation/FileProvider/NSFileProviderItemFields) values, like [`lastUsedDate`](/documentation/FileProvider/NSFileProviderItemFields/lastUsedDate) or [`tagData`](/documentation/FileProvider/NSFileProviderItemFields/tagData). Similarly, the dictionary doesn’t include the 32 bits of Finder info stored in an extended attribute named `com.apple.FinderInfo`, because this information exists in other [`NSFileProviderItemProtocol`](/documentation/FileProvider/NSFileProviderItemProtocol) properties. Also, the resource fork is content and isn’t included in the extended attributes dictionary. If your extension detects remote changes to the resource fork, report these changes by modifying the item version’s [`contentVersion`](/documentation/FileProvider/NSFileProviderItemVersion/contentVersion) property. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)