I would tend to avoid rampant use of square brackets in node titles. Such use complicates or even thwarts some ways of linking to such nodes.

And, despite the strong preference to refer to the language as "Perl 6" not "Perl6", the nature of search tags is such that the tag for easy searching for "nodes related to Perl 6" is "perl6" because most search methods know that searching for "perl 6" finds things that mention "perl" and "6" (or, increasingly, even things that mention "perl" or "6", much to my annoyance and frustration).