When I used to click on a URL in a newsgroup article, nothing would
happen. I looked in Tools -> Options -> Attachments -> File Types and
the HTML handler was htmlview. So, I changed it to mozilla-firebird and
now the links are opening in Konqueror, just as if I'd run htmlview from
the command line!

I'd like to understand how htmlview works, and perhaps use that to
launch Firebird.