$ git clone -n https://src.fedoraproject.org/rpms/R-expm.git /var/lib/mock/f45-build-6069-346/root/chroot_tmpdir/scmroot/R-expm
Cloning into '/var/lib/mock/f45-build-6069-346/root/chroot_tmpdir/scmroot/R-expm'...
$ git fetch origin a2166b3dd8773a623ec2177f3a5b233e1fca91b9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-expm
 * [new ref]         a2166b3dd8773a623ec2177f3a5b233e1fca91b9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a2166b3 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild