$ git clone -n https://src.fedoraproject.org/rpms/R.git /var/lib/mock/f40-build-787518-134786/root/chroot_tmpdir/scmroot/R
Cloning into '/var/lib/mock/f40-build-787518-134786/root/chroot_tmpdir/scmroot/R'...
$ git fetch origin 5eafc1034d0547838189dc8a1e0225a56752f695:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R
 * [new ref]         5eafc1034d0547838189dc8a1e0225a56752f695 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5eafc10 Update to 4.3.3