$ git clone -n https://src.fedoraproject.org/rpms/backintime.git /var/lib/mock/f40-build-1965532-25205/root/chroot_tmpdir/scmroot/backintime
Cloning into '/var/lib/mock/f40-build-1965532-25205/root/chroot_tmpdir/scmroot/backintime'...
$ git fetch origin 765bebc61da4c84f9c93d65d601ab7ef64f8aa07:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/backintime
 * [new ref]         765bebc61da4c84f9c93d65d601ab7ef64f8aa07 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 765bebc Update to 1.5.2