This is a bookmark for Hex Workshop and it describes XDBF/GPD files. All information can be found at http://free60.org/XDBF.
How to use:
1) open the included GPD file in Hex Workshop.
2) open the bookmark with the file.
3) view detailed information.
Note:
This Bookmark will not work with all GPDs because they all can be different (dynamic offsets), so be sure to use the one included for viewing.