==================
- Fix the interface definition of ``IRootFolder`` to give ``IRoot``
higher priority than the folder and container interfaces. This is
what is usually expected, but not what the code defined. Commonly,
in the past, this problem was hidden because the factory function
``rootFolder()`` re-arranged the interfaces to put ``IRoot`` at the
front. Under zope.interface 5's C3 resolution order, however, this
rearrangement was not taking place; thus, looking up adapters for a
``rootFolder()`` object was likely to find adapters for
``IItemContainer`` instead of adapters for ``IRoot`` as intended.
With this change, users of ``rootFolder()`` should notice no changes
compared with zope.interface 4. Code that has classes defined to
implement ``IRootFolder`` directly, though, may notice a different
resolution order on those objects (consistent with what
``rootFolder()`` generates).
See `issue 17 <https://github.com/zopefoundation/zope.site/issues/17>`_.