perlsource.pod: Misleading discussion of what should go into ext/

pod/persource.pod describes the 'ext/' directory in the Perl 5 
distribution thus:

"This directory contains XS-using modules which are only released as
part of the core."

Excerpting some discussion on #p5p:

08:41 rafl the XS bit for ext/ is also wrong, fwiw
...
08:49 kid51 By my count, there are 35 subdirectories under ext/, but 
only 28 with .xs
08:50 vincent pure-perl non-dual-lifed modules that are not needed to 
build other extensions can be put in ext/ as well
08:54 kid51 Errno FileCache IPC-Open3 Pod-Functions Pod-Html Tie-Memoize 
Win32CORE
08:54 kid51 those are the subdirs of ext/ without .xs

1. How can we more precisely describe what distributions should go under 
'ext/' (and, by implication, lib/, dist/ and cpan/)?

2. Are there any distributions currently under 'ext/' which should not 
be there?  Where they should go?

Thank you very much.
Jim Keenan

• perlsource.pod: Misleading discussion of what should go into ext/ by James E Keenan