The current implementation is of draft-04
It is serial 009 010 cset b05b1e9d1b1d 6cda09e18094 on try
source is at
https://tbpl.mozilla.org/?tree=Try&rev=b05b1e9d1b1d6cda09e18094
Builds for windows, os x, and linux are at
http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/mcmanus@ducksong.com-b05b1e9d1b1d6cda09e18094/
feedback of any sort welcomed to pmcmanus@mozilla.com