apply_filters( 'gallery_style', string $gallery_style )

2902	 *2903	 * @since 2.5.02904	 *2905	 * @param string $gallery_style Default CSS styles and opening HTML div container2906	 *                              for the gallery shortcode output.2907	 */2908	$output = apply_filters( 'gallery_style', $gallery_style . $gallery_div );2909 2910	$i = 0;2911 2912	foreach ( $attachments as $id => $attachment ) {2913 2914		$attr = ( trim( $attachment->post_excerpt ) ) ? array( 'aria-describedby' => "$selector-$id" ) : '';