dovecot/rootfs/etc/confd/templates/10-mail.conf.tmpl

mail_location = maildir:/var/lib/vmail/mail/%d/%n/Maildir
namespace inbox {
  separator = /
  inbox = yes
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }

  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }

  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }

  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
}

mail_plugin_dir = /usr/lib/dovecot