Ingo is an email filter rules manager.

Ingo currently supports the following filtering drivers:

    * Sieve (using timsieved) [FRAMEWORK_3, RELENG_1 and HEAD]
    * procmail (using VFS FTP driver) [FRAMEWORK_3, RELENG_1 and HEAD]
    * IMAP client-side filtering [FRAMEWORK_3 and HEAD]

Ingo has replaced IMP's internal filtering code and is the default
filtering agent in IMP H3.