There's an entire section for Playstation 4 improvements but only a few scant mentions of Xbox One.
Are consoles done in parity, or is UE4 favoring PS4 development over XB1?
it's probably that the xbox is better supported currently actually. I think the xbox has historically had better support (Gears of War probably pushed a lot of code into the engine)
http://www.techradar.com/news/gaming/consoles/ps4-s-outselli...
Engine vendors follow where the install base is.