Approver is a set of scripts for automatically approving posts to Majordomo-moderated mailing lists based on the sender's email address. Approver also converts HTML email posts to plain text by first filtering them through DEMIME, and it bounces all posts submitted to mailing lists made by non-list members, preventing list moderators from being bombarded by bogus submissions created by email worms and viruses originating from list member's infected computers.
Archetypes is a framework for developing new content types in Plone. The power of Archetypes is first in automatically generating forms, second in providing a library of stock field types, form widgets, and field validators, third in easily integrating custom fields, widgets, and validators, and fourth in automating transformations of rich content.
Arri provides an interface for accessing arrays in a safe manner that means that it is impossible to cause an overflow and, if the array is set to hard (it normally is), truncation. In addition to simply providing an interface for handling arrays, it also provides interfaces for using the arrays such as an IO API.