A key whose value is a persistent reference to the item.
- iOS 2.0+
- macOS 10.6+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The corresponding value is of type
CFData. The bytes in this object can be stored by the caller and used on a subsequent invocation of the application (or even a different application) to retrieve the item referenced by it.