Extension found in Onan 5500 generator compartment

I gather this is a 30 amp RV. the Forward/Aft switch is common on those (NOTE in one position they may both run when using the generator)

That 120 volt cord (you have likely never seen a 120 AMP connector. I am not sure I have and we use some serious amperage lighting a stage)

If it is 'Single ended" (hard wired to something) look for an outlet near where it connects.. Likely runs the rear A/C.

if it is just an extension cord. then it's just an extension cord.