The Fedora 31 and EPEL 6 chroots are marked as EOL in Copr now (for the epel
case, it's not even easily possible to build there nowadays because CentOS
already stopped mirroring of the repos).
There's additional 180 days period when we keep the build results. If you want
to keep the results longer than that, don't forget to periodically check your
EOLed chroots: https://copr.fedorainfracloud.org/user/repositories/