You can search for identifiers within the package.
in-package search v0.2.0
val error : ('a, unit, string, exn) Stdlib.format4 -> 'a
val return : 'a -> 'a Lwt.t
val fail : exn -> 'a Lwt.t
val set_fixed_string : Cstruct.t -> string -> unit
val starts_with : string -> string -> bool