This document is supposed to be a repository of "special characters"
used in Cyrus naming of users, folders, directory paths, etc.

--- Current Uses ---
Character: +
  - (LMTP) Separation of postuser and target mailbox for delivery
  - (LMTP) Separation of username and submailbox for delivery
  - (IMAP) Flag at end of login name that indicates that LIST should
    return LSUB results (when imapmagicplus is set)
  - (POP3) POP a subfolder directly (e.g. rjs3+foo POPs user.rjs3.foo)

Character: . /
  - [mailbox names] Hierarchy separators

Character: ^
  - [mailbox names] In unixhierarchysep, ^ is the part of the internal
    name that represents a '.'

Characters: @ %
  - [usernames] These are realm separators for the purposes of authentication

--- Future Uses ---

Character: +
  - IMAP LIST filters (e.g. rjs3+foo will only list folders that match foo*)
    -- possibly other interpretations here:
     - rjs3+foo will do an effective chroot(foo.)
     - rjs3+foo will only list folders in user.rjs3.foo*