You can search for identifiers within the package.
in-package search v0.2.0
type _ witness = ..
module type Tid = sig ... end
type 'a t = (module Tid with type t = 'a)
val make : unit -> (module Tid with type t = 's)
type ('a, 'b) teq =
| Teq : ('a, 'a) teq
val eq : 'r 's. 'r t -> 's t -> ('r, 's) teq option