Comment 32 for bug 25830

I one-shot solution (via the unknown type dialog) would be fine, but I'm more
interested in a permanent solution, i.e. an option in the preferences to always
show type "foo/bar" raw (as text).

I think mozilla should ship with an entry for text/* that has this option
enabled. Treating any text subtype that is not known as text/plain is actually
MIME standard behaviour. I don't consider that part an enhancement.

Example: http://people.debian.org/~jaqque/debian-issue.sh returns text/x-sh,
which mozilla should display as text.