new-content – Short-cut to all custom post types and original ones
comments – Comments moderation
appearance – Theme selection and Widgets
Parameter $node takes an array of arguments:
id
(string) (required) The ID of the node.
Default: false
title
(string) (optional) The text that will be visible in the Toolbar. Including html tags is allowed.
Default: false
parent
(string) (optional) The ID of the parent node.
Default: false
href
(string) (optional) The ‘href’ attribute for the link. If ‘href’ is not set the node will be a text node.
Default: false
group
(boolean) (optional) This will make the node a group (node) if set to ‘true’. Group nodes are not visible in the Toolbar, but nodes added to it are. See add_group().
Default: false
meta
(array) (optional) An array of meta data for the node.
Default: array()
‘html’ – The html used for the node.
‘class’ – The class attribute for the list item containing the link or text node.
‘rel’ – The rel attribute.
‘onclick’ – The onclick attribute for the link. This will only be set if the ‘href’ argument is present.
‘target’ – The target attribute for the link. This will only be set if the ‘href’ argument is present.
‘title’ – The title attribute. Will be set to the link or to a div containing a text node.
‘tabindex’ – The tabindex attribute. Will be set to the link or to a div containing a text node.
See https://developer.wordpress.org/reference/hooks/admin_bar_menu/ for examples
Since this is practically an alias for `add_node` method, you can find more information, specially about $args, here:
https://developer.wordpress.org/reference/classes/wp_admin_bar/add_node/