Name this wire

Hey all,
Finally got the bike altogether after the starter issues and she's running great! Actually got her around the block a couple times this evening. Only thing, I can't find where this wire below goes to. It's a tan color and has the round connector on it, so I'm thinking it goes to the frame. As far as I can tell, everything works perfect so have no idea what it's supposed to go to. Looking at the wiring diagrams, the only thing I can find is the rear brake light, however that already has a tan wire going to it.

Any help? Thanks!

You say Tan colour, are you sure it isn't pink that has discoloured? if so it might be the battery voltage sensor.

Just looking at the colours on your tank graphics, the blue looks lighter than the standard dark blue...Is it paint or a decal. and do you know if it is original?

I agree it looks like the voltage sensor wire which would be pink and connects to the bel artery. Where does the wire go to at the other end?

It may be discolored, just like everything else on this bike.

However, when the bike is running, if I press the voltage button I get a reading on the volt gauge.
I was unable to trace to where it goes without taking apart that whole loom. Should I try connecting to the battery and see what happens? Would it be (+) or (-)?

The tank is from a GPz, no clue how original all the colors and stuff on there are.

Yikes.... If you do that... at least use a voltmeter first or put a 12v bulb in series with it in case it is hot with battery voltage.