Link to documentation in error emails
Currently, if a subscriber receives an error email (e.g. due to their encryption key being missing/unusable) it is infuriatingly unhelpful:
You missed an email from list@lists.example.com because your subscription isn't associated with a (usable) OpenPGP key. Please fix this.
Kind regards,
Your Schleuder system.
Please fix this HOW? The email should contain some actual instructions. Even a simple link to the documentation would be an improvement. :-)
(The same logic applies to all other error emails)