As another cross-browser extension developer I too welcome this change. Firefox Add-on SDK was at best annoying and so inconsistent -- some APIs being sync and

As another cross-browser extension developer I too welcome this change. Firefox Add-on SDK was at best annoying and so inconsistent -- some APIs being sync and some async etc. I had to prepare an elaborate build system to have a single codebase (well, excluding Safari which is even worse). Now it'd be possible to move pretty far with Chrome/Firefox/Opera/Edge without the need to hack around the differences.