A section titled "How to setup JSF in a Java EE 6 webapp" would be good for the refguide, because it's funny how poorly this is documented.
to activate jsf, you need one of three things
1. seam-faces jar (that sets up jsf for you)
2. if not #1, you need empty faces-config.xml (root element only, can't be blank)
3. if not #1 or #2, you need web.xml w/ the Faces Servlet defined
mention the schema versions required, such as the one for faces-config.xml and web.xml