public function column_default( $item, $column_name ) {
		/**
		 * Fires for each registered custom link column.
		 *
		 * @since 2.1.0
		 *
		 * @param string $column_name Name of the custom column.
		 * @param int    $link_id     Link ID.
		 */
		do_action( 'manage_link_custom_column', $column_name, $item->link_id );
	}