Help identifying wires

[behindbars1544]

Hi guys. Name is Jay and I'm new to the forum, and to GM vehicles in general. Just purchased my first GM truck and I'm trying to work out the bugs. It's an 05 Yukon XL. It came with an aftermarket stereo in it which was a single din and in the extra space under it was a wire that looks like it should connect to an ipod or something like that. I tried connecting it to my phone and playing music but it didn't seem like anything was coming out so I took the head unit out and took some pictures. I know there not great but can anybody give me an idea of what the hell I got going on here?

I know the blue square box is for my SWC and onstar integration but I'm lost otherwise.








Thanks!!