I was also confused by the post that @PhilTheBeat2360 linked above. Here’s the link again:
This post says that Orbx was somehow involved in a long list of airports. I’ve checked out a few of these airports, and there are definitely changes. For example, before the USA update Kahului, Maui (PHOG) had a bunch of orphan jetways unattached to any terminal building. Now, there is a nice-looking terminal, and all the jetways are properly attached! Also, Kalaeloa, Oahu (PJHR) has a control tower now (it didn’t before the update), but the tower looks like one of the generic models that Asobo uses. Truckee, CA (KTRK) didn’t look especially impressive when I did a touch-and-go there yesterday, but I didn’t see any orphan jetways or buildings that looked out of place.
My guess is that these are mostly airport layout improvements, but I’d be interested in more details.