When Microsoft allow anyone to develop apps for the Xbox One platform (which they announced a while ago) there'll be homebrew starting to be made, but, there won't be anything to boot games using that as, well... the system is still not accepting everything to be loaded, and likely you'll have to get yourself into the developer program to use the homebrew that wasn't approved by microsoft/released on xbox live
There's rumours going around and has been for ages that we're close to a Xbox One hack, technically yeah, we are... but... it's nowhere near JTAG/RGH functionality...