....But I thought it was pretty cool.
Recursive Ray Acoustics using JAVA-VRML?
http://web.nps.navy.mil/~brutzman/vrtp/rra/
After googling around I found a few other obscure references, mostly having to do with RRD programming, pie charts using XML, and the Rail Roader's Association (I had no idea they were so big).
The link above seemed to be the best defined, but I doubt this is what the file format is for. There is chance that this link AND the XML Charts results I saw could be linked some way. I didn't spend too much time researching, but hopefully this points you in the right direction
BTW, what is in the file?
-AM