libmono-corlib4.5-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 Core Library (mscorlib.dll) of Mono for CLI 4.5,
 which is the glue between the BCL (Base Class Libraries) and the JIT.
 .
 You should install libmono-i18n-west4.0-cil if you are using
 ISO 8859-15 (Latin 9) or other common Western European code pages.
 US-ASCII, ISO 8859-1 (Latin 1) and UTF-8 users don't need any extra I18N
 packages.