> >(13)  LISTSERV messages  in MIME  format  for messages  to list  owners,
> >postmasters, and in response to commands.
>
> Could you  elaborate on that?  Most of these  messages are plain  text. I
> don't see how MIME could enhance, say, "You have been added" messages, or
> then the command response messages.
 
I agree that it wouldn't do much for a "You have been added message".
One case where it would be useful is when bounce messages are sent
to list owners and postmasters.  They could be made MIME multipart
messages with LISTSERV's text as one part and the bounce message as
another part.