Wow, this is awesome!
My OS is heavily scripted and keybound, thanks to 15 years of cumulative incremental fixes and a kick-ass WM. The one thing that's frustrated me is the relative black box that my browser represents, and writing a shim between my WM and browser tabs has been on my TODO list for a long, long time (through a couple of aborted attempts due to a combination of Chrome's at-the-time obsolete documentation and probably-necessary security model).
I'm cautiously optimistic that this is going to represent a dramatic step function in ease-of-use of my OS, in the same way that i3 was.
EDIT: I should clarify that I did read the author's note that this is experimental, not secure, etc. I'm mainly just excited about having a jumping-off point to play around with and possibly hack on a little.