libmono-microsoft-csharp4.0-cil 5.18.0.240+dfsg-3 (amd64 binary) in ubuntu eoan

 Mono is a platform for running and developing applications based on the
 ECMA/ISO Standards. Mono is an open source effort led by Xamarin.
 Mono provides a complete CLR (Common Language Runtime) including compiler and
 runtime, which can produce and execute CIL (Common Intermediate Language)
 bytecode (aka assemblies), and a class library.
 .
 This package contains the Mono Microsoft.CSharp library version 4.0.