Global variables and contextual variables have been unified to both use the * twigil. I'll look into updating the Differences document (which usually lags behind the synopsis documents). (Update: I removed the mention of + in the svn, it'll take at most an hour until the HTML version shows up correctly).

For better resources on Perl 6 I recommend following the links on http://perl6-projects.org/, especially the blogs. I admit it's a bit hard to see how up-to-date the individual pages are.