I think richthomas is right in thinking it came from the wifi. I just looked at the wifi block but I can't see any place where it might connect. I think it must be a very small post that the wire snaps on to and it looks like the wire is the right length for a wifi connection. Do you know where on the wifi module it should attach. Again it looks like the loose end (wifi end) of the wire has some kind of solderless connection. Here is a picture of the wire connection and the wifi module it should connect to somewhere.
Thanks All
Kman