In the email that the Let’s Encrypt Expiry Bot sends there is a link to unsubscribe.
The paragraph is misleading, it should be
If you want to stop receiving all email to this address, click
If you want to stop receiving all email from this address, click
Unsubscribing from this address refers to the domain address — ex. “www.example.com” — not the email address you are receiving the notification in proper english.
If you receive multiple emails for different certificate you would think you are unsubscribing for a specific domain but in effect you are unsubscribing from all the notices you are receiving at that email address.