$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rdiscount.git /var/lib/mock/f45-build-35259-694/root/chroot_tmpdir/scmroot/rubygem-rdiscount
Cloning into '/var/lib/mock/f45-build-35259-694/root/chroot_tmpdir/scmroot/rubygem-rdiscount'...
$ git fetch origin dbf1717635dac4aef3e7d75f57ba77a35ac1310d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rdiscount
 * [new ref]         dbf1717635dac4aef3e7d75f57ba77a35ac1310d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dbf1717 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild