You can search for identifiers within the package.
in-package search v0.2.0
val either : ('a -> 'c) -> ('b -> 'c) -> ('a, 'b) result -> 'c
module type T = sig ... end
module Make (T : T) : sig ... end
module ErrS : sig ... end
val filter_rev_map : ('a -> ('b, 'c) result) -> 'a list -> 'b list