You can search for identifiers within the package.
in-package search v0.2.0
type !'a formator = 'a -> string
val def_int : int formator
val def_string : string formator
val def_bool : bool formator
val product : 'a formator -> 'b formator -> ('a * 'b) formator
val product3 : 'a formator -> 'b formator -> 'c formator -> ('a * 'b * 'c) formator
val option_format : string -> string -> 'a formator -> 'a option formator