I continue down the rabbit hole to an interesting question… What is UScene for? I have traced as much as I can around, my only guess is maybe something to do with the Editor…
I Understand UWorld which has a list of ULevels which each also have ULevelScriptActors for blueprints… but I can find no reference anywhere to what a UScene object is or does.
It is an artifact from when a reflected header required a UCLASS() declaration in order to be valid (there are other examples in various headers, such as UInputCoreTypes). It can be totally ignored and will probably be removed at some point.