Comment by ghuntley

Yes. FreeBSD and OSX support was done 100% by the open-source community w/ support from MSFT whom helped a little bit with domain knowledge (the CLR product managers and developers can be found in the Gitter room)

See https://news.ycombinator.com/item?id=9431368 w/ Microsoft .NET CoreCLR is now running on FreeBSD 10.1 (amd64)