You can search for identifiers within the package.
in-package search v0.2.0
type (_, _) eq =
| Refl : ('a, 'a) eq
type 'a t
val make : unit -> 'a t
val eq : 'a t -> 'b t -> ('a, 'b) eq option
val cast : 'a t -> 'b t -> 'a -> 'b option