You can search for identifiers within the package.
in-package search v0.2.0
type 'a t =
| Make : {
arg : 'a Arg.t;
summary : string;
readme : (unit -> string) option;
} -> 'a t
| Group : {
default : 'a Arg.t option;
subcommands : (string * 'a t) list;
val summary : _ t -> string
val map : 'a t -> f:('a -> 'b) -> 'b t