As expected, Microsoft today announced that CoreCLR is now open source on GitHub. CoreCLR is the .NET execution engine in .NET Core. It is responsible for functions such as garbage collection and compilation to machine code. They have released the complete and up-to-date CoreCLR implementation, which includes RyuJIT, the .NET GC, native interop and many other .NET runtime components.
Today, .NET Core builds and runs on Windows. We will be adding Linux and Mac implementations of platform-specific components over the next few months. We already have some Linux-specific code in .NET Core, but we’re really just getting started on our ports. We wanted to open up the code first, so that we could all enjoy the cross-platform journey from the outset.
You can check out the CoreCLR sources, fork, clone and build.
Read more about it here.