I have a 04 Talon ZX and have the fuel cell in the rear, the only lines from it go to the generator compartment. I'm guessing it was used to fuel the gen set only, as there is no other hose.
The PO took the gen set out, so now it's just storage for me, and I use a portable Honda generator when needed.
TV - 01 F250 Powerstroke
TH - 04 Talon ZX 36Z