$ git clone -n https://src.fedoraproject.org/rpms/sane-backends.git /var/lib/mock/f40-build-1936847-25145/root/chroot_tmpdir/scmroot/sane-backends
Cloning into '/var/lib/mock/f40-build-1936847-25145/root/chroot_tmpdir/scmroot/sane-backends'...
$ git fetch origin a0257d974ab6972401a88d8ccc7c3246b685243b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sane-backends
 * [new ref]         a0257d974ab6972401a88d8ccc7c3246b685243b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a0257d9 2263985 - sane-backends-1.3.1 is available