$ git clone -n https://src.fedoraproject.org/rpms/R-NISTunits.git /var/lib/mock/f41-build-side-1-3142748-40009/root/chroot_tmpdir/scmroot/R-NISTunits
Cloning into '/var/lib/mock/f41-build-side-1-3142748-40009/root/chroot_tmpdir/scmroot/R-NISTunits'...
$ git fetch origin b2bd2e454f018bf481a1bf127383c6794bf996a7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-NISTunits
 * [new ref]         b2bd2e454f018bf481a1bf127383c6794bf996a7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b2bd2e4 convert GPLv3+ license to SPDX