nsIFile:lastModifiedTimeOfLink
From MDC
[edit] Summary
This attribute exposes the time when the symbolic link referenced by this nsIFile was last modified.
attribute PRInt64 lastModifiedTimeOfLink;
[edit] Remarks
Unlike lastModifiedTime, this attribute corresponds to the last modified time of the symbolic link referenced by this nsIFile. If this nsIFile does not reference a symbolic link, then the value of this attribute is undefined.
The value of this attribute is milliseconds since midnight (00:00:00), January 1, 1970 Greenwich Mean Time (GMT).
Changing the last modified time of a nsIFile operates on the underlying filesystem. As of Mozilla 1.7, changing the last modified time of a non-existent file has undefined behavior.