What Is This Cable Behind The Tape?

I have this same cable idle behind the tape. The radio of my original tape is not very good, I thought it might be an antenna socket, but I could not find a place to plug it in the back of the tape. Anybody have an idea?

they might have done for an extra cable aux etc

I don't think it's an antenna. It looks like the socket of an external tape. I looked like a navigation antenna.