Anyone know what this wire is for?

I’m swapping out my reg tomorrow on the X11, and intend to replace it with a mosfet I have in the loft. All the wires make sense on the honda set up, apart from a wire that appears to run to the bank angle sensor, which I assume is an anti tilt jobby. It doesn’t link to anything else, and think it has to be a live, although I’ll test it tomorrow
Does anyone know if this additional wire performs a secret function that will prevent me from using a non honda reg? Why does the tilt sensor take a feed directly from the reg?
Is it so if the battery has disintegrated, and the rider falls off, the bike will still know because it gets a preferential electrickery supply? Can I just take a spur off one of the other live outputs? (assuming it IS a live feed)

Try CBRXX.COM some Fi owners might know, miner a carbie and different

Reg/Rec is a Honda weakness