There was a news article about DevKit SDK release for Xbox One.
To open up Dev functions on the Xbox One, first, you need to obtain the so-called Sandbox ID from Microsoft, and second, get a special version of the console – DevKit Unit, which could only be licenced from Microsoft. Of course you need to step into legal agreements with Microsoft on all of these, stating your real name and other personal data. As the scene is mostly anonymous, the release of DevKit SDK will not be of much help to jailbreak it.