The plane parked off to the side of the normal ramp space that the A300s use.
I have two possibilities:
1.) The plane came here to do some testing of the HUD technology developed by a local company.
2.) The MD-11 might be used at MHT and FedEx was familiarizing ground crews with the aircraft.
I put a whole lot more credence into #1 rather than #2, but no one has been able to verify why N579FE was here.