[SOLVED] path substitution – what does “server side” mean?

hello
i’m setting up path substitution on my farm. i understand fields named ‘linux’, ‘mac’ and ‘windows’. of course i also know what does ‘path name’ field do. but what is ‘server side’ field for? is it for integrated web server? can somebody explain, please?

edit:
“Server side” stands for path seen by dispatcher.

(Thanks for explanation Leonardo)