You can search for identifiers within the package.
in-package search v0.2.0
module Key : sig ... end
val hash_fold_t : (Ppx_hash_lib.Std.Hash.state -> 'a -> Ppx_hash_lib.Std.Hash.state) -> Ppx_hash_lib.Std.Hash.state -> 'a t -> Ppx_hash_lib.Std.Hash.state