I'm not necessarily suggesting a third FF derivative. I do prefer Iceweasel
to either of the other two.
Iceweasel is a Firefox derivative.
I would vote for that, though commented is already a step in the right
direction.
My point is that I wonder if having FallbackDNS undefined in
/etc/systemd/resolved.conf really does not set any fallback DNS. It may be
that Google's DNS are still used as a fallback, that FallbackDNS must be
defined to nothing to really not have a fallback. Defining to nothing is
enough according to
https://bugs.debian.org/cgi-bin/bugreport.cgi?att=0;bug=761658;msg=216
As the link above states: "systemd-resolved is not used and enabled by
default". I would add: it is a fallback, i.e., only used when no DNS server
is configured (when you connect to Internet, a DHCP server administrated by
your Internet provider sends you the addresses of its DNS servers). So,
well, it is not a grave problem...
