I was thinking about renaming default_mail_env to something that is more understandable. I'll keep it working for backwards compatibility anyway. How about:
# Location for users' mailboxes. This is the same as the old default_mail_env # setting. The default is empty, which means that Dovecot tries to find the # mailboxes automatically. This won't work if the user doesn't have any mail # yet, so you should explicitly tell Dovecot the full location. # # If you're using mbox, giving a path to INBOX file (eg. /var/mail/%u) isn't # enough. You'll also need to tell Dovecot where the other mailboxes are and # where Dovecot can place its index files. # # There are a few special variables you can use, eg.: # # %u - username # %n - user part in user@domain, same as %u if there's no domain # %d - domain part in user@domain, empty if there's no domain # %h - home directory # # See doc/variables.txt for full list. Some examples: # # mail_location = maildir:/var/mail/%1u/%u/Maildir # mail_location = mbox:~/mail/:INBOX=/var/mail/%u # mail_location = mbox:/var/mail/%d/%n/:INDEX=/var/indexes/%d/%n # # http://wiki.dovecot.org/MailLocation # #mail_location =