If it isn't an operating system, it shouldn't be called an operating system.

He isn't trying to rethink the desktop/workstation OS. If he's found a way of improving upon existing desktop environments, it should be clear what improvements he's made and how he has made them.

It seems it's written in Node Webkit (NW.js), which - if I understand correctly - allows you to build desktop applications in the same way node.js allows you to build applications which run in the browser. He appears to have used this to prototype a desktop environment. Rewriting a desktop environment, for efficiency, in C and using Xlib would itself be a major undertaking.