Grasshopper.Kernel.Special namespace

Is it possible to obtain documentation for the Grasshopper “Special” namespace?

I just know this documentation
https://developer.rhino3d.com/api/grasshopper/html/723c01da-9986-4db2-8f53-6f3a7494df75.htm

Yes, I know that one. But there is a Grasshopper.Kernel.Special namespace that I see being used in various C# scripts and that namespace doesn’t show up in the API list.