Modules that provide backwards-compatibility to some features that were added later:

Perl 6

• Perl6ish
  • Perl6::Perl
  • Perl6::Slurp
  • Perl6::Caller
  • Perl6::Take
  • Perl6::Say
  • Perl6::Contexts
  • Perl6::Junction
  • Perl6ish::Syntax::temp
  • Perl6ish::Syntax::state
  • Perl6ish::Syntax::constant
  • Perl6ish::Array
  • Perl6ish::Hash
  • Perl6ish::String
  • Perl6ish::Syntax::DotMethod

Perl 5.10

• named captures
  • Regexp::DeferredExecution
  • Perl6::Rules
  • Regexp::NamedCaptures

other

• ppport.h