[Zope-dev] Confused: Does PersistentList exist?

I found seceral seemingly up to date docuemnts claiming that both PersistentMapping and PersistentList exists and is included with Zope. However, I couldn't find PersistentList, so I thought that it had been added after 2.3.3, which I am using. So I checked the CVS. Nope, nothing there. So whats the deal here, really?