$ git clone -n https://src.fedoraproject.org/rpms/erlang-lfe.git /var/lib/mock/f40-build-1507240-23890/root/chroot_tmpdir/scmroot/erlang-lfe
Cloning into '/var/lib/mock/f40-build-1507240-23890/root/chroot_tmpdir/scmroot/erlang-lfe'...
$ git fetch origin b17520945b790c2acf68aca86e0bfbee50211703:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-lfe
 * [new ref]         b17520945b790c2acf68aca86e0bfbee50211703 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b175209 Switch to Rebar3