Earlier this week, Microsoft started taking sign-ups for Project xCloud, its upcoming game streaming service. There are two parts to the service though. That will enable you to stream games to your phone from the cloud, but you'll also be able to stream games from your own console, using it as a server.
That part of the service is going live soon, at least in preview for Xbox Insiders. If you're on the Alpha or Alpha - Skip Ahead rings, you can now test out your console, controller, and network to make sure it's compatible.
Both rings are getting new builds to enable it. If you're on the Preview Alpha ring, you'll get build 18363.8060 from the 1911 development branch, and those on Skip Ahead will get build 18992 from the 2004 development branch. Both of them have the same new features.
After installing the build, you can go to Settings -> Network settings -> Test console streaming to try it out. It will then check if your console, controller, and network "pass the test", and it will let you know if any components aren't compatible.
The other thing listed in the changelog is support for Google Assistant. This is actually a feature that was announced yesterday, and should be available for everyone.
Update: An earlier version of this article said that the Console Streaming feature is now live. It's not. You can simply test your hardware to make sure it will work.