At its Build developer conference today, Microsoft announced that it was open sourcing a wide array of its .NET libraries and related technologies and creating a group, the .NET Foundation, to oversee the development and stewardship of the open source components.

Perhaps the highlight of the announcement today was that the company will be releasing its Roslyn compiler stack as open source under the Apache 2.0 license. Roslyn includes a C# and Visual Basic.NET compiler, offering what Microsoft calls a “compiler as a service”.