MR is just Microsoft branding. The new headsets are VR headsets with integrated tracking cameras so their is no need for Vive-style Lighthouse trackers or Rift-style external cameras.
People also fling critique at Magic Leap for the same problem, since it is very clearly an AR device.
So there is support for augmented reality, but it looks like most if the demos currently being made are for VR.
It would make a lot of sense, but there is no support in the API for the low cost devices for doing any of these things. The cameras are purely used for tracking purposes at this point and none of the HoloLens-style AR experiences that would seem to make sense are possible with this generation of low cost MR headsets and APIs.
Unfortunately this isn't the case. It's just pure VR.