[Zope] Zopebook and license.

Hi all, i have a question about Zopebook. The first edition of Zopebook was under OPL, so the terms of usage and redistribution are clear and precise. However the same thing doesn't happen for the second version of the book. Version 2.6 has no license attached. We are planning to translate the book in italian, but now there is a question: under which license will be the translation released? And most important, is it possible to make changes to the book? Thanks, Paolo