Severity: minor

The Conkeror website says:

    "Conkeror was originally written for Xulrunner, which was deprecated
    by Mozilla a couple of years ago ... [Firefox 52 ESR] reached end of
    life on September 5 2018, to be replaced by a Quantum-based release.
    That means there will be no more officially supported browser from
    Mozilla on which to run Conkeror.  As modern web browsers have a
    large attack surface, this is bad if you have any concerns about
    security.  Here are some possible alternatives."
    From: http://conkeror.org/Alternatives

I think it's time to mark browse-url-conkeror obsolete.

Please see the attached patch.

Best regards,
Stefan Kangas