Apparently, List-Unsubscribe and friends are not something that just mailman and few other geeks use :) :
http://www.ietf.org/rfc/rfc2369.txt
http://www.list-unsubscribe.com/
https://support.google.com/mail/answer/81126
It can't surely be expected to magically fix bug 52915, but it can't harm.
Actually, this would be nice to have also in core enotifs.
Version: master
Severity: normal