The text file used to be produced by FIP but I'm not sure if it even is any more.
Flavors of the old Parrot flight code and some prototype FIPs were floating around (see the Featherweight forum), but neither the current FIP nor the Raven flight code are.
What's known:
The char mapping and multiplier that FIP currently has is:
X=Axial Accel (Gs),0.01
Y=Lateral Accel (Gs),0.01
T=Temperature (F),0.01
b=Volts Battery (V),0.001
a=Volts Pyro Apogee (V),0.001
m=Volts Pyro Main (V),0.001
3=Volts Pyro 3rd (V),0.001
4=Volts Pyro 4th (V),0.001
C=Current Draw (A),0.001
P=Baro (Atm),0.00004
A=[Altitude (Baro-Ft-AGL)],1.0
V=[Velocity (Accel-Ft/Sec)],0.1
sampling rates:
440 Hz: X axial acceleration * 100
220 Hz: Y radial acceleration * 100
40 Hz: C output current
20 Hz: everything else