You can search for identifiers within the package.
in-package search v0.2.0
type path
val mkdir : path -> int -> unit
val stat : path -> MinUnix.stats
val lstat : path -> MinUnix.stats
val readdir : path -> string array
val rmdir : path -> unit
val remove : path -> unit
val basename : path -> string
val dirname : path -> path
val add_basename : path -> string -> path
val to_string : path -> string