XTF questions can be directed to Steve
Tinney.The XTF format is a complex XML format for representing various kinds of editions of cuneiform texts in transliteration. It is not intended that XTF be entered manually by users; rather, data should be keyboarded in ATF (ASCII Text Format) which is converted to XTF using a parser documented on the ATF-Tools page.
Although there is presently no separate XTF documentation, the DTD is heavily commented and can be browsed to good effect.