$ git clone -n https://src.fedoraproject.org/rpms/R-covr.git /var/lib/mock/f45-build-6034-345/root/chroot_tmpdir/scmroot/R-covr
Cloning into '/var/lib/mock/f45-build-6034-345/root/chroot_tmpdir/scmroot/R-covr'...
$ git fetch origin 42474d37afce10c21a84ce1e73e6837a5a0daef0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-covr
 * [new ref]         42474d37afce10c21a84ce1e73e6837a5a0daef0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 42474d3 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild