You can search for identifiers within the package.
in-package search v0.2.0
type 'a t = 'a IO.t
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
val (>>) : 'a t -> 'b t -> 'b t
val return : 'a -> 'a t
type ic = IO.ic
type oc = IO.oc
val iter : ('a -> unit t) -> 'a list -> unit t
val read_line : ic -> string option t
val read : ic -> int -> string t
val read_exactly : ic -> int -> string option t
val write : oc -> string -> unit t