Yangqing here from facebook. We consciously made it a MIT license as onnx is intended to be widely shared by a lot of participants, and MIT seems to be more widely agreeable among different parties co-owning it. It's also simpler.
Interesting, it is also MIT instead of the usual BSD + Patents Facebook uses. [1]
It is also under the 'onnx' namespace, presumably because it was a team effort.
It looks like Microsoft often uses MIT (vscode, dotnet, CNTK, ChakraCore), does this mean Microsoft was the driving force (even though it's a Facebook blog)?
* just noticed the link to Microsofts blog at the bottom of the page [2].