nsILocalFile:persistentDescriptor
From MDC
[edit] Summary
This attribute exposes a platform-specific, unique string representation of this nsILocalFile.
attribute ACString persistentDescriptor;
[edit] Remarks
On some platforms, the value of nsIFile::path may be insufficient to uniquely identify the file on the local filesystem. The persistent descriptor is intended to be used whenever a nsILocalFile needs to be serialized to disk and later recovered.
Note, the value of the followLinks attribute is not encoded in the persistent descriptor.