This is a ScriptCS script pack that brings in features of the ClrMD API which can then be used for scripted or interactive diagnostics (via REPL) against any running CLR process.
For an introduction to ClrMD and its API you can check out this blog post on the .NET Framework Blog.
Check out the Interactive Diagnostics with the ScriptCS REPL section of the Wiki for a quick introduction to using ScriptCs.ClrMD in REPL mode.