/usr/lib/ocaml/nproc/META is in libnproc-ocaml-dev 0.5.1-2build4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | version = "0.5.1"
description = "Process pool"
requires = "lwt.unix"
archive(byte) = "nproc.cma"
archive(native) = "nproc.cmxa"
|