/usr/lib/ocaml/METAS/META.llvm is in libllvm-ocaml-dev 1:3.4-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ocaml/METAS/META.llvm-3-4
/usr/lib/ocaml/METAS/META.llvm-3-4