$ git clone -n https://src.fedoraproject.org/rpms/erlang-cowboy.git /var/lib/mock/f45-build-8252-382/root/chroot_tmpdir/scmroot/erlang-cowboy
Cloning into '/var/lib/mock/f45-build-8252-382/root/chroot_tmpdir/scmroot/erlang-cowboy'...
$ git fetch origin c287d4beced95a40ed3f3256ac0fd610efc0295e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-cowboy
 * [new ref]         c287d4beced95a40ed3f3256ac0fd610efc0295e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c287d4b Rebuilt for libxml-2.5.4