http://gnuzilla.gnu.org/filters/ is up again.
However, https://gnuzilla.gnu.org/ is not mirrored to
http://gnuzilla.gnu.org/filters/, instead it reads:
Index of /
Free GNU/Linux distributions
dragora/
dragora/ ISO images
dynebolic/
gnewsense/
musix/
parabola/
trisquel/
trisquel-images/
ututo/
Other datasets
membercard/
pmon2000/
ryzom/
This is a mirror of some of the free
distributions we list on gnu.org/distros and a few other
large data sets (e.g., the FSF membership card, Ryzom
artwork). Feel free to download or mirror the distros from there,
preferably using rsync. While we provide copies of these distros
for you for convenience, they are put together and maintained by
others and are outside our control.
If you are maintaining a free distro, please contact FSF sysadmin to have your
distro
mirrored here.