I am using CMF 1.5.2 and Zope 2.8.0 - will upgrading again this week to 1.5.3 and 2.8.1 I removed my BTreeFolder2 product as it was indicating it was duplicated product in my event log after my recent upgrade - so it appears to have become part of the distribution.
It is part of 2.8, yes, so you will not need to install BTreeFolder2 separately in that case (you did not mention version numbers in your original mailing).
I did not really understand the difference between a BTreeFolder2 and a CMFBTreeFolder since CMFBTreeFolder did not appear as content even though it is displayed as an option in Core Content in ZMI.
Content type registration for the ZMI and for CMF are two different things. An item showing up in the ZMI does not mean it exists in the types tool. A CMFBTreeFolder is just a BTreeFolder2 with all the necessary trimmings so it plays nice with CMF. Portal buildout upon instantiation and types creation is handled through CMFSetup XML-based profiles. There is no way to express "If product A is installed, install type B". So for CMF 1.5, which can be run on Zope 2.7 and 2.8, you will have to do this step manually, tough luck, nothing you can do about it. In CMF-HEAD, which depends on Zope 2.8 and thus guarantees the availability of BTreeFolder2, it is an oversight that CMFBTreeFolder is not one of the automatically installed types upon portal instantiation. I filed a collector issue and will look at it over the next couple days: http://www.zope.org/Collectors/CMF/371 jens