[Zope] PersistentList is missing

Sorry if me or grep is blind but I can't find the class PersitentList in the sources of Zope2.5.0: cd zope/lib/python; grep -irs persistentlist * --> no result http://www.amk.ca/zodb/guide/node38.html and other sources tell me that there is something like this in ZODB. Has Zope just a subset of the available classes of ZODB? thomas