It’s all relative to the device which has to playback the script.
Multi-axis players translate funscripts into TCode and it is specified like this.
https://github.com/multiaxis/tcode-spec
I think this is how the channels are mapped.
L0: stroke
L1: surge
L2: sway
L3: suck, valve
R0: twist
R1: roll
R2: pitch
V0: vib
V1: pump
TCode is also relative to the device which interprets it.