I would think that its just a spigot for the filter to screw on to, it should ha-ha just undo, you know, just like the exhaust nuts do. The safest bet is to get a parts diagram if Haynes doesnt cover it but I doubt its anything other than a male/male reducer bolted in at the factory probably after the engine is in the frame, the fact that its got a hex on it makes it look like it comes out, but then your entire bike has a hex on it at the moment !
I hope it works out for you, youve more patience than I have in this weather.