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filter is not described

get_object_subtype_(object_type) filter-hook . WP 4.9.8

Filters the object subtype identifier for a non standard object type.

The dynamic portion of the hook, $object_type, refers to the object type (post, comment, term, or user).

Usage

add_filter( 'get_object_subtype_(object_type)', 'filter_function_name_3921', 10, 2 );
function filter_function_name_3921( $object_subtype, $object_id ){
	// filter...

	return $object_subtype;
}
$object_subtype(string)
Empty string to override.
$object_id(int)
ID of the object to get the subtype for.

Where the hook is called

get_object_subtype()
get_object_subtype_(object_type)
wp-includes/meta.php 1399
return apply_filters( "get_object_subtype_{$object_type}", $object_subtype, $object_id );

Where the hook is used (in WP core)

Does not used.