front-end hooks status?

What is the status on the Hooks proposal/documentation/implementation? I'd like to try it out on a pet project. trac/ghc/wiki/Ghc/Hooks is promising, but I don't know where to find the patch to experiment with it. I get a 404 from https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-hooks-reco..., a link I found in one of Luite's ghc-devs emails. Exciting work! Thanks.