A YouTube video from Gametuts has made the rounds and exposed a quick way to hypothetically turn any Xbox One into a dev kit. Microsoft has responded by suggesting you not follow these steps, and that doing so puts you at your own risk.
All that is needed to unlock the dev kit mode is access to the Settings > System menu and a quick push of Left Bumper, Right Bumper, Left Trigger and Right Trigger. Doing so will enable a dev kit option, and clicking that will request a Sandbox ID for the console.
An Xbox One Developer on Reddit, user name XboxOneDev of all things, chimed in to warn against activating the option.
"Please don't mess with anything here for the time being, especially the sandbox ID. You risk putting your box into a boot loop."
He went on to confirm that he has "no idea how far along the [email protected] program is. There are many concerns such as privacy, security, stability etc., that need to be sorted out before we can allow anyone and everyone to simply sideload an app onto their box."
Xbox Corporate Vice President Marc Whitten confirmed that every Xbox One could hypothetically become a dev kit, but that the option would not be available at launch. Best leave it alone for now and not open it until Microsoft has a more concrete response.
You're meddling with powers you can't possibly comprehend.