Hi.. I'm a lurker here hoping to learn how to help you all by osmosis
of your interactions on this list. I just played along and went to the
above site. Received this on Iceweasel:
+++
mentors.debian.net uses an invalid security certificate. The
certificate is not trusted because the issuer certificate is unknown.
(Error code: sec_error_unknown_issuer)
+++
I don't know if it has any bearing or not but, during a recent near
daily upgrade, I just accidentally happened to actually "see and
(almost) grasp the significance" that ca-certificates was upgraded in
the last few days. A quick grep through /var/log/apt shows that was
just the 20th (~3 days ago per my term.log). Would that maybe play any
part in this?