wp_admin_bar_add_secondary_groups( WP_Admin_Bar $wp_admin_bar )

function wp_admin_bar_add_secondary_groups( $wp_admin_bar ) {
	$wp_admin_bar->add_group( array(
		'id'     => 'top-secondary',
		'meta'   => array(
			'class' => 'ab-top-secondary',
		),
	) );

	$wp_admin_bar->add_group( array(
		'parent' => 'wp-logo',
		'id'     => 'wp-logo-external',
		'meta'   => array(
			'class' => 'ab-sub-secondary',
		),
	) );
}