There is an issue on Github that is collating the problems they are working through. I've lost track of it, though, unfortunately. I've been pretty cynical about it in the past, but the last time I looked at the issue, it does look more complex than I first imagined. I wish it were higher priority, though. Hopefully somebody will remember the issue and post it here (it was from an HN post that I found it originally). Unfortunately, I'm not even sure what project it's under and there are many projects.