add_action( 'admin_bar_menu', 'add_link_to_admin_bar', 999 );
function add_link_to_admin_bar($wp_admin_bar) {         
    // adds a child node to site name parent node
    $wp_admin_bar->add_node( array(
      'parent' => 'site-name',
      'id'     => 'plugins',
      'title'  => 'Plugins',
      'href'   => esc_url( admin_url( 'plugins.php' ) ),
      'meta'   => false
    ));
}