This article is regarding the Approvals app.
You can define who an approval needs to be granted by based on either the Zendesk user or which organisation the ticket was submitted from, as explained in the 'managers' article here.
When a manager is unable to grant approval for some reason, the approval may need to be escalated up the chain of command either manually or automatically after a period of time. As such, you're able to set which Zendesk user field contains the email address of the 'Escalation path manager'. Here's a video to help explain things: