WP_Sitemaps_Provider::get_sitemap_type_data()

	public function get_sitemap_type_data() {
		$sitemap_data = array();

		$object_subtypes = $this->get_object_subtypes();

		// If there are no object subtypes, include a single sitemap for the
		// entire object type.
		if ( empty( $object_subtypes ) ) {
			$sitemap_data[] = array(
				'name'  => '',
				'pages' => $this->get_max_num_pages(),
			);
			return $sitemap_data;
		}

		// Otherwise, include individual sitemaps for every object subtype.
		foreach ( $object_subtypes as $object_subtype_name => $data ) {
			$object_subtype_name = (string) $object_subtype_name;

			$sitemap_data[] = array(
				'name'  => $object_subtype_name,
				'pages' => $this->get_max_num_pages( $object_subtype_name ),
			);
		}

		return $sitemap_data;
	}