??
... so?
What provision on that page would I violate if I made an FLOSS project based on UE4?
... so?
What provision on that page would I violate if I made an FLOSS project based on UE4?
Unreal's license for obtaining the source does not permit you to redistribute in source form, so you can't comply with their license and still fulfil that point.
While it's certainly trivial now for most anyone to obtain that source independently, you can't include that source in your own project while still distributing your own project under any license that the OSD would label as open source.
So no way UE4-based project will be FLOSS or even open source.