$ git clone -n https://src.fedoraproject.org/rpms/cockpit-machines.git /var/lib/mock/f39-build-1867558-42580/root/chroot_tmpdir/scmroot/cockpit-machines
Cloning into '/var/lib/mock/f39-build-1867558-42580/root/chroot_tmpdir/scmroot/cockpit-machines'...
$ git fetch origin 631ab7c104ee6578610e6fd6d28f0744458c5fab:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cockpit-machines
 * [new ref]         631ab7c104ee6578610e6fd6d28f0744458c5fab -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 631ab7c [packit] 303 upstream release