You can search for identifiers within the package.
in-package search v0.2.0
module T : sig ... end
type ('a, 'b) s = ('a, 'b) T.t
type t
val inj : ('a, 'b) s -> ('a, ('b, t) app) app
val prj : ('a, ('b, t) app) app -> ('a, 'b) s