string $object_subtype, int $object_id )
Filters the object subtype identifier for a non-standard object type.
The dynamic portion of the hook name,
$object_type, refers to the meta object type (post, comment, term, user, or any other type with an associated meta table).
Possible hook names include:
(string) Empty string to override.
(int) ID of the object to get the subtype for.