$ git clone -n https://src.fedoraproject.org/rpms/backintime.git /var/lib/mock/f42-bootstrap-3462105-45558/root/chroot_tmpdir/scmroot/backintime
Cloning into '/var/lib/mock/f42-bootstrap-3462105-45558/root/chroot_tmpdir/scmroot/backintime'...
$ git fetch origin e906973add75fc990dbeb7e245d6f62a49a88169:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/backintime
 * [new ref]         e906973add75fc990dbeb7e245d6f62a49a88169 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e906973 update to 1.5.4