When a subscriber clicks the unsubscribe link, they are taken to a landing page where they can verify their unsubscription.
This is a standard unsubscribe page used as the default for all mailings, but you can also create your own pages for unsubscribing and resubscribing under Settings if you want to design a custom page.
If you add your own URL, an HTML code will be generated that you can place on the page to add the verification button for the unsubscription.
