You can search for identifiers within the package.
in-package search v0.2.0
type t = directory
val dirname : t -> t
val basename : t -> t
val reach_from : dir:t -> string -> t
[Invalid_arg
_] if parent/name exists but is not a directory.
parent/name
val mkdir_p : t -> unit
val of_string : string -> t
val to_string : t -> string
val ls : t -> file list
module Table : Hashtbl.S with type key = t