.NET Core
.NET Core is a new FOSS software framework from Microsoft for C#, Visual Basic, and F#. It is designed to be cross-platform, modular and apt for modern applications, as opposed to its predecessor, the .NET Framework.
Installation
If you only want to run .NET Core managed applications, install the dotnet-runtime package.
To build apps with .NET Core, install dotnet-sdk as well.
Microsoft recommends using Visual Studio Code , their Electron-based FOSS IDE, to build & debug .NET Core apps.