What are Anchor and Passthrough used for in popover segues?

Question

In Xcode, a Popover segue has two connection fields named Anchor and Passthrough. What are they used for?

Answer 1

These are properties of the UIPopoverController, not the segue. Thats why if you look at the documentation for the UIStoryboardPopoverSegue, you won't find these two properties.

The anchor is telling the UIPopoverController where to point its arrow.

The passthrough is an array of views that the user can interact with while the UIPopoverController is displayed.

The documentation is here: https://developer.apple.com/documentation/uikit/uipopovercontroller

and the section going over the passthrough views is here: https://developer.apple.com/documentation/uikit/uipopovercontroller/1624654-passthroughviews