Frankenstein Build

Hey Ladies and Gents!

Long time forum stalker, first time poster…
First off, this community is great and has been extremely helpful in providing context and insight as I dive into a project I’m working on.
I recently acquired a 1978 XS750 with the objective of bringing it back to life and going full cafe racer. It’s been a project I’ve wanted to take on for a while and I’ve finally made the leap. I have a background in motorcycles as I’ve grown up around them my whole life, and I have a background in maintenance as a crew chief in the USAF. I know helicopters and motorcycles don’t directly translate but it’s better than nothing.

I am aiming to diagnose a few things before I invest too much time and money, ie that electricals are good, and then engine, carbs, etc are in good order. Currently there is no sign of life from the bike from an electrics perspective and I’m wondering if I’m missing something. I’ve installed a new battery, checked fuses, and ground wire and from what I can see, everything looks good. However there is one wire that I’m not sure what purpose it serves or where it should be connected. I’ve included photos in this post. It’s a wire that goes to one of the ignition coils and then has a disconnected end by the battery.
Any thoughts as to what this might be? And any general words of wisdom as to what might be preventing the bike from sparking?

thanks again in advance for the help and I’m looking forward to being a part of this forum.