Auxilliary Power Bonneville T120 2021 For Gps ?

Hi,

I recently started mounting and cabling a GPS to my Bonneville T120 Model 2021.
Before now cutting the connection to the USB-Outlet under the seat and mounting the GPS-connection there in addition, I wanted to clarify:

• I recently heard about an additonal spare auxilliary cable on the T120, which to my understanding would perfectly fit to my aims.
• Does anyone know, if that exists also on my model, the 2021 T120.
  In an older youtube-video (which I can't find anymore...) there was mentioned that this spare cable supposed to by under the tank, but I could not find anything there.
• In case it is there (where?), is it always connected to power or is it switched with ignition?
  
• I could not find any wiring diagrams for my model, also the Haynes Repair Manual only exist for the previous model: https://haynes.com/en-gb/triumph/bonneville-t120/2016-2019
  ==> Does anyone know how close these two models are, would it make sense to buy the repair guide for the older one?

Thanks for any help
Jogi