Access-type "local-file" means the body can be found in a file on the
local file system, whatever that may be. The only additional required
parameter is the "name" parameter, although the "site" parameter can
also be used to define the domain of locality (i.e. where this file
system is believed to exist).
The utility of `local' is good & obvious. I feel the `site' parameter
should be mandatory if only because 1) NFS (or other network file systems)
are not installed `everywhere', and 2) even for systems with NFS
installed a reference/mount from a remote system need to place it in the
same location as on the local system.