public function render_index( $sitemaps ) {
		header( 'Content-type: application/xml; charset=UTF-8' );

		$this->check_for_simple_xml_availability();

		$index_xml = $this->get_sitemap_index_xml( $sitemaps );

		if ( ! empty( $index_xml ) ) {
			// All output is escaped within get_sitemap_index_xml().
			// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
			echo $index_xml;
		}
	}