Waste cap strap?

[PEJensen]

1. There is an 8" cable or wire attached to the black tank discharge valve cover plate. the other end of the cable is not attached to anything. At first I thought it might be a ground wire. But now I wonder if it was originally attached to the waste cap, to keep it from being lost. The current waste cap doesn't look like it was ever attached to the cable, but it may be a replacement. I have attached a picture so you can see what I am talking about. Why it is upside down, i have no idea. This is on a 2004 25' Classic. What is the cable supposed to be attached to?

[BayouBiker]

You are correct that is not the original waste cap and the cable was to keep the original cap from getting lost.