Core is an industrial-strength alternative to the OCaml standard library. It was developed by Jane Street, which is the largest industrial user of OCaml.
Core provides an overlay on the usual namespace, so the best way to use Core is to start your file with:
open Core
In the case of bugs, feature requests and similar, you can contact us at opensource@janestreet.com. You can find all of Jane Street's open-source libraries on our github account. Documentation can be found here.