$ git clone -n https://github.com/xcp-ng-rpms/ssmtp.git /var/lib/mock/v8.3-incoming-9091-27939/root/chroot_tmpdir/scmroot/ssmtp
Cloning into '/var/lib/mock/v8.3-incoming-9091-27939/root/chroot_tmpdir/scmroot/ssmtp'...
$ git fetch origin 8864ecabc3afb3c6f407a67179c4fffa0e3003ef:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/ssmtp
 * [new ref]         8864ecabc3afb3c6f407a67179c4fffa0e3003ef -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8864eca Import ssmtp-2.64-15.xs8.src.rpm