Available file systems will be found at the same path regardless of physical location, and are implicitly authenticated by their path names — as they include the public-key fingerprint of the server (hence why it is called "self-certifying").
File systems that can be accessed will be located at the same site irrespective of their physical placement, and are automatically validated through their path names — since these contain the server's public-key signature (therefore earning its name as "self-attesting").