You can search for identifiers within the package.
in-package search v0.2.0
module Ser : sig ... end
module De = De
val serialize : (module Ser.Intf with type error = 'a and type output = 'b) -> Ser.data -> ('b, 'a Ser.ser_error) result
type data
module type Serializable = sig ... end
val let* : ('a, 'b) result -> ('a -> ('c, 'b) result) -> ('c, 'b) result