"Can I use my retail Xbox One as a developer kit?
Not yet. For developers working on Universal Windows Apps, you’ll be able to test your games on a retail Xbox One sometime after the second half of 2015. Selling UWAs on Xbox One will come in 2016."
http://www.xbox.com/en-AU/Developers/id
Looks like sometime this year, Universal Windows App for Win10 will run on Xbone.