This is not a rumor so much as it is an early preview. Reddit’s verified XboxOneDev has revealed external drive support is coming to the Xbox One.
Of course, responses to this announcement have been overwhelmingly positive, although some fans are pointing out that this is a necessary feature, and of course, implicit in that is that Xbox One should have had this enabled from the start.
For those wondering, the screenshot shows 29.4 % of the hard drive was used, with 585.9 GB free to use. Doing the math, that amounts to roughly an original amount of 758 GB.
As we know, the Xbox One has three USB 3.0 ports. This was originally intended to use Xbox One USB accessories. As of right now, there are actually only three officially supported accessories: the MadCatz Arcade Fightstick TE 2, the Thrustmaster TX Racing Wheel Ferrari 458 Italia Edition, and the Xbox One Play and Charge Kit.
So, this really is a welcome addition to the console’s features, to make better use of its capabilities as well. Unfortunately, we don't know when the feature will actually be added yet, although we received a promise of more information soon. We will keep you up to date when more information relating to this feature is revealed.