It tries to open https://extdist.wmflabs.org/dist/extensions/CheckUser-REL1_35-cebf4be.tar.gz but results in a HTTP 404 error
Looking at https://extdist.wmflabs.org/dist/extensions/ there's a file for CheckUser-REL1_35-b8c0dab.tar.gz from 23-Oct-2022 07:05, apparently the failure is very recent.
Looks like disk is full. I'm going to guess what broke it was that it started to have to make tarballs for 1.39
bawolff@extdist-06:/srv$ df -h Filesystem Size Used Avail Use% Mounted on udev 2.0G 0 2.0G 0% /dev tmpfs 394M 444K 393M 1% /run /dev/sda1 20G 12G 7.7G 60% / tmpfs 2.0G 0 2.0G 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock /dev/sda15 124M 5.9M 118M 5% /boot/efi /dev/sdb 9.8G 9.3G 0 100% /srv tmpfs 394M 0 394M 0% /run/user/0 tmpfs 394M 0 394M 0% /run/user/1235 bawolff@extdist-06:/srv$ du -hs * 3.1G dist 300K extdist du: cannot read directory 'lost+found': Permission denied 16K lost+found 6.3G src bawolff@extdist-06:/srv$
Mentioned in SAL (#wikimedia-cloud) [2022-10-25T07:36:59Z] <bawolff> Increased disk size to 22 GB (T321488)