$ git clone -n https://src.fedoraproject.org/rpms/libmodbus.git /var/lib/mock/f45-build-16562-487/root/chroot_tmpdir/scmroot/libmodbus
Cloning into '/var/lib/mock/f45-build-16562-487/root/chroot_tmpdir/scmroot/libmodbus'...
$ git fetch origin a985e6c68668120a59253dfd03ab0eaff410be91:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libmodbus
 * [new ref]         a985e6c68668120a59253dfd03ab0eaff410be91 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a985e6c Remove stale 'xmlto' and 'asciidoc' BuildRequires