It uses the friendfeed.py library provided by at friendfeed-api and stores the data fetched from FriendFeed in your local database so it won't have to be reloaded for each pageview.
Be aware that by using FriendFeeds's API through this module, you are bound by their terms of service.
Zwei means "two" in German. The reason this project is not just named "django-friendfeed" is that there is an earlier project by the same name.
Django Friendfeed Zwei is not based on that code due to an incompatible license (GPL3). The original django-friendfeed seems to have been abandoned. At the time of this writing, the code has not been touched for more than a year.