$ git clone -n https://src.fedoraproject.org/rpms/erlang-webmachine.git /var/lib/mock/f40-build-1848564-24974/root/chroot_tmpdir/scmroot/erlang-webmachine
Cloning into '/var/lib/mock/f40-build-1848564-24974/root/chroot_tmpdir/scmroot/erlang-webmachine'...
$ git fetch origin d812fb24b5e3a78ec7c6b0b16384c078f1f108c2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-webmachine
 * [new ref]         d812fb24b5e3a78ec7c6b0b16384c078f1f108c2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d812fb2 Remove outdated comment