I think that's just a NC-10 (or whatever the AF designation is) for power. The umbilical wouldn't be able to move any air since it's kinked up (and has a really small diameter).
This F-35B was parked along side AF A-models. The contrast in material condition of the planes was dramatic.
The young Marine maintainers shared that the cleaning and upkeep of the F-35B is a nightmare on and off the boat and NAVAIR procedures and consumables to even wash the airplane are far more labor intensive and less effective than their AF counterparts...