$ git clone -n https://src.fedoraproject.org/rpms/root.git /var/lib/mock/f41-build-1714147-24614/root/chroot_tmpdir/scmroot/root
Cloning into '/var/lib/mock/f41-build-1714147-24614/root/chroot_tmpdir/scmroot/root'...
$ git fetch origin dafa5d9be68997265dd02220b91dcf5cbc41b3d5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/root
 * [new ref]         dafa5d9be68997265dd02220b91dcf5cbc41b3d5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dafa5d9 Update ROOT's R interface for Rcpp 1.0.13