Mono is an open source implementation of .NET Development Framework. Its
objective is to enable UNIX developers to build and deploy cross-platform
.NET Applications. The project implements various technologies developed by
Microsoft that have now been submitted to the ECMA for standardization.

Mono provides the necessary software to develop and run .NET client and
server applications on BSD, Linux, Solaris, Mac OS X, Windows, and Unix.

SPECTRE MITIGATION: Mono 6.4+ introduces additional internal changes to
better protect against Spectre and Meltdown attacks for both compiled and
interpreted code during runtime. This can cause severe performance impacts
to applications in a number of scenarios, and is not enabled by default for
that reason. When used in high risk environments such as shared hosting,
it is strongly recommended to enable this option.

WWW: http://www.mono-project.com/