$ git clone -n https://src.fedoraproject.org/rpms/R-RPostgres.git /var/lib/mock/f41-build-side-1-3141181-39987/root/chroot_tmpdir/scmroot/R-RPostgres
Cloning into '/var/lib/mock/f41-build-side-1-3141181-39987/root/chroot_tmpdir/scmroot/R-RPostgres'...
$ git fetch origin a6682e9396fc20e72560db450a076be3457d8bba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-RPostgres
 * [new ref]         a6682e9396fc20e72560db450a076be3457d8bba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a6682e9 convert GPLv3 license to SPDX