Tangentially related, one nice feature of Proton Mail is that it has an unsubscribe button on the toolbar. You don't have to go to web sites and jump through hoops.
I have never seen/used Proton Mail, but I suspect
unsubscribe at the email client level is equivalent to training SpamSieve that the message is SPAM. In other words although you don't see the message, it still gets sent and still takes up internet bandwidth.
Neither does the sender get any information or feedback — that could be good or bad depending on your point of view.
