You typically don't supply the actual filesystem path when querying 'remotely': svn list svn://localhost/myproject
As a user you don't really know (or care) where the server actually stores the files themselves. It's the service's job to figure that out. You're only interested in the server and the repository name.
Similar to a web request for http://www.example.com/dir/file.txt. The actual directory where /dir/file.txt is stored on the server is not known and could be anywhere. It's the job of the web server to translate this according to it's configuration to find the actual files.