[Dovecot] clarify 'type', 'executable' & 'path' in 2.0 master.conf?

@2.0's master.conf, there's, e.g.,

service config { type= config executable =config unix_listener { path = config mode = 0666 } }

can someone please explain function/usage for the 'type', 'executable' & 'path' fields?

and, for any file paths, are the presumed to be _relative_ to the dovecot executable? in $PATH? can they accept full/absolute paths?

thanks.