You can search for identifiers within the package.
in-package search v0.2.0
type t = string
val empty : string
val length : string -> int
val append : string -> string -> string
val lowercase : string -> string
val iter : (int -> 'a) -> string -> unit
val of_string : 'a -> 'b
val to_utf_8 : ('a -> 'b -> 'c) -> 'd -> 'e -> 'f
val compare : String.t -> String.t -> int