> XS [is] exclusive to Perl 5.
Perl 5 modules, including XS ones, are `use`able with P6 (`use Module::Using::XS:from<Perl5>; # P6 code...`).
> CPAN [is] exclusive to Perl 5.
CPAN has been an optional store for Perl 6 modules since 2016 iirc. In the last couple months it's become more or less the preferred store.