$ git clone -n https://src.fedoraproject.org/rpms/onboard.git /var/lib/mock/f39-build-1533960-36231/root/chroot_tmpdir/scmroot/onboard
Cloning into '/var/lib/mock/f39-build-1533960-36231/root/chroot_tmpdir/scmroot/onboard'...
$ git fetch origin 6cd24c41669abdd3c12f7dc263764b4e657caa05:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/onboard
 * [new ref]         6cd24c41669abdd3c12f7dc263764b4e657caa05 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6cd24c4 Disable autostart for cinnamon session