It's very likely that when I was doing this it was nmh 1.6 that was
running here. And the things I remember needing to add was a
different mimetype for pgp signatures and a whole host of mimetypes
for things that that supposedly generated 'internet business cards,
and calendaring information', a bad idea whose time I think has come
and gone. But for a while everybody seemed to be sending me one,
and everybody had their own idea as to what the name of the mimetype
was.
Alright, this makes a little more sense now.
In general, nmh should have just ignored content it couldn't display.
But I believe what was happening with that particular release was that
there was a fallback entry in the Debian nmh configuration for things like
"application" or "text" that didn't match any other rule and it wanted
to use run-mailcap on it, and maybe that was failing due to a missing
mailcap entry. Also, we've improved MIME handling for 1.7. Like I
said people would have to check current Debian systems for what it
is doing now.
I guess I just wanted to correct the assertion that nmh uses a mailcap
file; it does not, except for some certain Debian releases.
--Ken