A look at Archetypes

All Plone content types including everything in FSD, like people and departments are written atop a framework called Archetypes, which provides much of their complex behavior:

• The familiar multi-tab Edit pages

• Widgets little snippets of user interface for displaying and editing various types of fields: dates, simple and styled text, images, so on

• Logic for storing content in and retrieving it from the ZODB or elsewhere