What is it?

While test driving a 2001 Grand Marquis yesterday my wife noticed some type of unknown knob. It is at the bottom of the dash, passenger side, above the hump. I forgot to look at it when we got out. Anybody know what it would be?

Is it just to the right of the hump? It's probably the auxiliary 12v power source (same as a cigarette lighter). A good place to plug in a GPS without having to have the ash tray pulled out.