Where does one find syntax descriptions for IIS URL Rewrite condition input variables?

Question

The need to understand what the variable represents and also perhaps examples of what it contains would be helpful. I've seen such postings for URL Rewrite of Apache in the documentation, but nothing official for IIS that I can see.

I'm trying to understand what all these mean:

Answer 1

IIS Server variables

IIS server variables provide information about the server, the connection with the client, and the current request on the connection. IIS server variables are not the same as environment variables.

http://msdn.microsoft.com/en-us/library/ms524602(v=vs.90).aspx