So if the files are not out there for public use, how were the GM ones obtained?
Stuff leaked out or was "tossed" out the back door. The last thing to appear was the datastream defs. For a long time the only thing out there was the ecmguy hacs and maybe one or two other independently done files. Then stuff started showing up here and there which had GM written all over it. The 7749 and $58 are so well documented because someone in England got a copy of the GM variable list and made tuning software long before most of the gmecm guys were a cohesive group.

So anyone know if one for my factory jeep ecm could be found and made to work with tunerpro? Would be nice if I could atleast scan and mabey datalog my stock ecm, just to see whats going on.
One way to get an idea what's happening is to monitor the communications on the data line to / from scantool. This is how some of the early GM OBDII programming routines were worked out. Snap-on and others pay Chrysler for information from the data link so their scantools will work so it's not like it's a deep, dark secret. It's just an expensive secret.