Docker/Moby announced the 17.06 CE release today, however it's not clear to me how they actually crafted the 17.06 using moby.
There isn't 17.06 branch on the docker/moby github project, likewise no information on their moby project website.
They have the following depiction, but how to actually achieve such architecture isn't clear.
There are a few things going on here, both with the name "Moby".
This comes from the docker/docker-ce repo where they effectively vendor in pieces of moby/moby and other components in the components.conf file.
That should be moby/moby and the branches there are historical from the prior location in docker/docker (which now redirects).
This is where the Moby names get a bit confusing. The container engine formerly found at docker/docker was moved to moby/moby. Moby is also a project that acts as a landing space for everything Docker is giving to the community. And Moby is lastly part of a new OS project from the LinuxKit team that can create lightweight container based operating systems. The picture you shared is discussing the latter project where it's easy to extend that OS with your own components.
This gets into a longer range goal of Docker. They plan to redesign the engine and break of the monolith that has become the container engine. The goal is to turn the engine into a gRPC proxy that integrates with all the other components like libnetwork, swarmkit, etc. However, this is still coming out of the design stage. What already exists is the ability to add additional components in the OS based on the LinuxKit work, and of course all the source code is there in moby/moby along with docker/docker-ce for you to fork the code and create your own engine.
For more details, I've also written a blog post on the topic that goes into the different names and what's happening with them.