$ git clone -n https://src.fedoraproject.org/rpms/backintime.git /var/lib/mock/f42-build-side-1-3537696-46560/root/chroot_tmpdir/scmroot/backintime
Cloning into '/var/lib/mock/f42-build-side-1-3537696-46560/root/chroot_tmpdir/scmroot/backintime'...
$ git fetch origin 0687359e7e6e166fd5127b634c4c41089f18285c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/backintime
 * [new ref]         0687359e7e6e166fd5127b634c4c41089f18285c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0687359 update to 1.5.5