$ git clone -n https://src.fedoraproject.org/rpms/R-bench.git /var/lib/mock/f38-build-724203-99404/root/chroot_tmpdir/scmroot/R-bench
Cloning into '/var/lib/mock/f38-build-724203-99404/root/chroot_tmpdir/scmroot/R-bench'...
$ git fetch origin 49ee771d04720089d128cfd85ca4ec7351af9de1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-bench
 * [new ref]         49ee771d04720089d128cfd85ca4ec7351af9de1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 49ee771 R-maint-sig mass rebuild