During the initial API development that's in 1.5.0 Beta 2, a few parts of the API were marked with @Beta. In some cases, like with HitboxVRMovementInfo, this was done simply because it wasn't moved to the API yet. In other cases, like with the WorldStorage system, it was marked as @Beta because I no longer plan to include it in the API, but it's already partially there and needs to be moved.

By 1.5.0, nothing should be marked as @Beta. There should either be a proper implementation in API, or it should be moved out of the api package so its understood to only be used internally by ImmersiveMC.