IPhone 6S Plus extra wire to screen?

I am replacing the screen on this 6s plus and I seem to have an extra wire that goes from the top left of the battery up to screen. I have never seen this before and I have been searching youtube videos and still cannot find anything similar to this. Does anyone know what this wire labeled "a""b" is for? Thanks

https://drive.google.com/open?id=0BxWTuC5xhmMhUmVBbUk3UlpKZVE

https://drive.google.com/open?id=0BxWTuC5xhmMhdGxDaWF1Zks1WWs

No idea. However, you might be able to find out by going to www.ifixit.com and look up the instructions and take apart for screen replacement for the 6s+.

And, Welcome to our forums.

Thanks for the reply. I actually sent them an email. They didn't know what it was either and referred me to their instructions. I might just change the screen and leave that wire unhooked and see what happens. Thanks.

Maybe it relates to the Force Touch - or whatever it is called? I mean the pressure sensitive menu thing