[Buttons840]

Is .NET open-source? Will I find it in an open-source repository?

[NlightNFotis]

Yes.

https://github.com/dotnet/runtime/

[sva_]

Seems so https://github.com/dotnet/dotnet

[hexxington]

This is the "virtual monorepo", if you want to clone one repo and build the entire SDK product then this is the correct thing to checkout - but development work right now still happens in the separate project repos, of which there are ~20

[WorldMaker]

Also, the main languages:

https://github.com/dotnet/roslyn