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

[PGNet Dev]

@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.