A CompleteDataFeed is a DataFeed whose standard representation includes content for every item currently in the feed.

This is the equivalent of Atom's element as defined in Feed Paging and Archiving RFC 5005, For example (and as defined for Atom), when using data from a feed that represents a collection of items that varies over time (e.g. "Top Twenty Records") there is no need to have newer entries mixed in alongside older, obsolete entries. By marking this feed as a CompleteDataFeed, old entries can be safely discarded when the feed is refreshed, since we can assume the feed has provided descriptions for all current items.