I define "outside the core" as "anything that isn't packaged with Perl itself". Things you'd define as "part of the language." I/O stuff, threading stuff, standard types, builtin functions, etc. And yeah, most of that stuff will be written natively in C, PIR, or be part of parrot itself.
I think there will also be a much larger "standard library" that will be bundled separately, which would contain your libwww, libnet, and other widely/commonly used modules. The way I think of it is kinda like installing something with the windows installer: you can check to install the "minimal" or standard version, the "full" version (which would be perl + the "standard library"), or you could even check "custom" and choose what you'd like to install. And, of course, everything else would just be on the CPAN. - Joe
