$ git clone -n https://src.fedoraproject.org/rpms/R-Rmpfr.git /var/lib/mock/f41-build-side-1-3141211-39987/root/chroot_tmpdir/scmroot/R-Rmpfr
Cloning into '/var/lib/mock/f41-build-side-1-3141211-39987/root/chroot_tmpdir/scmroot/R-Rmpfr'...
$ git fetch origin 27d60b3d0e76c361f6062c8616a360204bfd7815:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-Rmpfr
 * [new ref]         27d60b3d0e76c361f6062c8616a360204bfd7815 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 27d60b3 convert GPLv2+ license to SPDX