Quarry is currently running on python 3.5 on Debian Stretch. This is the
current version still running at
quarry.wmflabs.org. A new version running
on python 3.7 on Debian Buster is now available at
quarry.wmcloud.org. To
any interested party please test there and we will cut over the old domain
to the new buster systems if no problems are found in a few days.