Card back sections support an optional action property to add a button at the top right

You can now return an action along with your card-back-section in order to show a button at the top right of your section.

An action consists of two required properties:

text - The text to show on the button
callback - The function to be called when the user clicks the button

Your callback can do anything a card-button callback can do, such as opening a t.popup or a t.modal for example.

Check out the full docs for the card-back-section capability for more information: