Indeed, it's called HyperKit[0][1], and it's based straight off xhyve[2].

Also, there's docker-machine-driver-xhyve for people that prefer using docker-machine (like I do) instead of DfM.

[0]: https://github.com/moby/hyperkit

[1]: https://blog.docker.com/2016/05/docker-unikernels-open-sourc...

[2]: https://github.com/moby/hyperkit/tree/master/src/