$ git clone -n https://src.fedoraproject.org/rpms/R-ps.git /var/lib/mock/f41-build-1280355-23185/root/chroot_tmpdir/scmroot/R-ps
Cloning into '/var/lib/mock/f41-build-1280355-23185/root/chroot_tmpdir/scmroot/R-ps'...
$ git fetch origin b008ff5c1dbd743cd4b4e0c5b757e7443e6f4474:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-ps
 * [new ref]         b008ff5c1dbd743cd4b4e0c5b757e7443e6f4474 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b008ff5 R-maint-sig mass rebuild