Strange flex cable around headphone jack on 5S. What is it?

On the iPhone 5S there is a strange flex cable around the headphone jack which is a part of the charge port assembly. I've always assumed it's some sort of "ground" or something like that but am looking for a little clarification on what it actually is. Also under the charge port assembly there is a bit of metal which I also assume is some type of "ground". I would consider myself an experienced repair technician (2 years in own repair shop) and have never had any problems with either the "strange flex cable" or "bit of metal" but am just curious as to what purpose they may serve. I would also like to know what they are if ever a problem should arise with either.

Cheers!

Tyler Alderman

Berkshire Wireless Repair