You can search for identifiers within the package.
in-package search v0.2.0
type ('a, 'b) x = ('a, 'b) t -> 'b
type ('a_s, 'b_s) t =
| [] : (unit, unit) t
| :: : ('a, 'b) x * ('a_s, 'b_s) t -> ('a * 'a_s, 'b * 'b_s) t