$ git clone -n https://src.fedoraproject.org/rpms/buildbot.git /var/lib/mock/f39-build-1665770-40755/root/chroot_tmpdir/scmroot/buildbot
Cloning into '/var/lib/mock/f39-build-1665770-40755/root/chroot_tmpdir/scmroot/buildbot'...
$ git fetch origin 74a9daca01b4d875bef7ba283adc8937cf5c8e7f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/buildbot
 * [new ref]         74a9daca01b4d875bef7ba283adc8937cf5c8e7f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 74a9dac Upgrade master DB and restart all masters and workers on upgrade