$ git clone -n https://src.fedoraproject.org/rpms/erlang-lager.git /var/lib/mock/f40-build-1625952-24117/root/chroot_tmpdir/scmroot/erlang-lager
Cloning into '/var/lib/mock/f40-build-1625952-24117/root/chroot_tmpdir/scmroot/erlang-lager'...
$ git fetch origin 757a6512236eef89fa2cbc6fdb8bcd777493737f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-lager
 * [new ref]         757a6512236eef89fa2cbc6fdb8bcd777493737f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 757a651 Fixed FTBFS with a modern Erlang