Two parts carrier board design for The Cube

Hey all.
I thinking of designing a two-parts carrier board, where one has the same footprint as The Cube and the other is not restricted by size, and is connected to The Cube via cable.
To understand if this is doable I’d like to understand actually how many of the wires that are connected to the 80pin connector I actually want to use.
I’ve seen the list here cubepilot wiki.
But there are quite a few pins that I don’t understand their function, and I’m afraid I’ll later find out that are needed.
Is there a source of information to understand the exact function of each pin?
I’ve seen @apache405 's library, but I’m not sure it’ll have the information I am looking for.

I am aware of the registration needed here.

You will be able to find all the answers you are looking for at this address :
The-Cube/CB_REV_C_Altium at master · proficnc/The-Cube · GitHub

Have fun !