https://www.codeguru.com/dotnet/net-nuts-bolts-the-joy-of-ro...
Or DotGNU?
https://www.gnu.org/software/dotgnu/
What happened to Xamarin looks like Microsoft took whatever IP was relevant, and left everything else go, which this decision is a confirmation thereof.
It is kind of interesting to see Miguel's feedback, now that he his allowed to talk about how things went down.