Earlier this year, Microsoft's Xbox corporate VP Marc Whitten stated that that all Xbox One consoles will eventually be able to work for development, something promised to come along but not be available when the console first launched. Despite still not being available, some industrious Redditor has discovered how to access the functionality in the consoles at the moment, something that has prompted Microsoft to issue a warning.
The menu is available by heading into the system menu and then excuting the following in order: left bumper, right bumper, left trigger, and right trigger. Doing so will pull up a dark menu that, on the far right side, lists "Developer settings" as an option. From there, you get a bit of access to what lies under the hood, with things like "Debug & Profiling" being listed.
Of course, we strongly advise that you do not do this, as tinkering where men shan't tread could result in all sorts of grief. Curiosity killed the cat and all that, and heading into the developer settings could kill your console, figuratively speaking. Microsoft concurs, and since the method surfaced, it sent the following statement over to the folks at Kotaku.
"Changing the settings in this menu is only intended for developers for Xbox One, and this alone does not turn the console into a development kit. We strongly advise consumers against changing these settings as it could result in their Xbox One becoming unusable. Customers who have put their consoles into this developer setting can revert by restoring factory defaults under Settings / System, select Restore Factory Defaults."