.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 dotnetAUR and dotnet-cliAUR.
To build apps with .NET Core, install dotnet-sdkAUR as well.
Microsoft recommends using Visual Studio Code, their Electron-based FOSS IDE, to build & debug .NET Core apps.
OmniSharp dependencies in VS Code
Arch is not officially supported by the Dotnet SIG, and attempting to install dependencies via the C# extension (OmniSharp) may fail.[1]
To fix this, install icu57AUR, and in the VS Code settings, set "csharp.fallbackDebuggerLinuxRuntimeId" to "ubuntu.16.04-x64". After restarting VS Code, open a C# source file to begin installing dependencies.