$*PERL<version> is not allowed nowadays but with .version we get a reasonable answer:
$ perl6 -e 'say $*PERL.version' v6.b
Christian Bartolomaeus via RT Thu, 22 Oct 2015 13:22:04 -0700
$*PERL<version> is not allowed nowadays but with .version we get a reasonable answer:
$ perl6 -e 'say $*PERL.version' v6.b