C&D from Blizz is what I heard. Research/commercial use is prohibited
edit: An issue was opened[0] but there has been no response. I find it hard to believe a C&D comes with a gag order but IANAL.
I find it frustrating there's no transparency on this, and I hope I'm not being overly dramatic, but I would have expected more openness here.
There could be a very reasonable explanation for keeping mum on this, I guess.