If that were my unit and I just took delivery I would had made a call to the dealer and asked what is was for. Not trying to be a smart a** with my response but from the picture it appears to have something to do with the generator Unless you just placed it on the manual. But there is no other information given as to what model it goes to.
2004 Jay Feather 25E
2001 Ford Expedition 4X4 EB 5.4 3.55 rear
2004 Ford Expedition 4X4 EB 5.4 3.73 rear