We've bit the bullet and will commit to releasing an Xbox One port of RetroArch for early 2019!
Might require Developer Activation and might not be available on the Store but will be possible for anybody with an Xbone to obtain nonetheless!
We basically have most of the building blocks ready for an Xbox One port, the only thing that still needs to happen is making an UWP app out of RetroArch.
Xbox One might be the only game console out of the big three so far that will not require you to jailbreak anything in order to run RetroArch.
Looks like that Xbox One RetroArch port might be coming much sooner than even we anticipated thanks to the efforts of krzys-h! Thanks so much for sending a PR for this!