This is an optional field that contains alphanumeric text to be displayed in the tooltip when the user right-clicks the node. This way, you can provide additional data to the user without cluttering the visual. 

You can also enter URLs in this field, and they will be clickable when displayed in the tooltip (some example use-cases: providing social media profile links or email addresses for each employee node, or website links for external stakeholders). 

If you wish to use custom display text for the link, simply format it using HTML hyperlink syntax. Replace the underlined example text with the URL and display text you want to use.

<a href="Example link">Example Display Text</a>