Klaviyo has a feature it seems, where each account has their own form page they can simply share with users who request to be unsubscribed from all mailings outside of the usual self serve unsubscribe links in footers as an example.
https://manage.kmail-lists.com/subscriptions/unsubscribe?cy=HEyw3X
Looks like it's a general base link of https://manage.kmail-lists.com/subscriptions/unsubscribe and the query string on the end cy=HEyw3X would be a customer specific token.
The use case is:
-someone emails customer directly (eg customer's support team) and requests to unsubscribe from all
-Support can send back a link to the unsubscribe form, where the requesting contact can enter their email address and be unsubscribed from all mailings
This can be accomplished today with a maropost form + landing page and a backend journey, but a baked in feature would be nice as well.