media_upload_tabs

		'library'  => __( 'Media Library' ),
	);

	/**
	 * Filters the available tabs in the legacy (pre-3.5.0) media popup.
	 *
	 * @since 2.5.0
	 *
	 * @param array $_default_tabs An array of media tabs.
	 */
	return apply_filters( 'media_upload_tabs', $_default_tabs );
}

/**
 * Adds the gallery tab back to the tabs array if post has image attachments
 *
 * @since 2.5.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *

	// to ensure plugins will work. We will then unset those tabs.
	$tabs = array(
		// handler action suffix => tab label
		'type'     => '',
		'type_url' => '',
		'gallery'  => '',
		'library'  => '',
	);

	/** This filter is documented in wp-admin/includes/media.php */
	$tabs = apply_filters( 'media_upload_tabs', $tabs );
	unset( $tabs['type'], $tabs['type_url'], $tabs['gallery'], $tabs['library'] );

	$props = array(
		'link'  => get_option( 'image_default_link_type' ), // db default is 'file'
		'align' => get_option( 'image_default_align' ), // empty default
		'size'  => get_option( 'image_default_size' ),  // empty default
	);

	$exts      = array_merge( wp_get_audio_extensions(), wp_get_video_extensions() );