If we add some URL resources into META files specified in CPAN META Spec, links back to the URLs would appear on metacpan pages; it might be so cool, I think. I wanted to do that for PrePAN at first. I hacked up Module::Install::PrePAN and sent a pull-req of metacpan code to prove my concept.
In the discussion we made at IRC and the GitHub board linked above, we saw the key name $meta{resources}{PrePAN} wasn't good. The reason why I used it was that the CPAN META Spec 1.4 specified unofficial keys must include at least one upper-case letter.
(Spec 1.1) [optional] {map} A mapping of any URL resources related to this distribution. All-lower-case keys, such as homepage, license, and bugtracker, are reserved by this specification, as they have ``official'' meanings defined here in this specification. If you'd like to add your own ``special'' entries (like the ``MailingList'' entry above), use at least one upper-case letter.
http://module-build.sourceforge.net/META-spec-v1.4.html#resources
On the other hand, version 2 of the spec doesn't and formalized all custom keys not listed in the official spec use "x_" or "X_". EU::MM and Module::Install seem to haven't supported the new spec around $meta{resources} yet. Module::Build has done already.
I thought `X_prepan' was more appropriate as a key name because it doesn't violate both of the specs and is the form version 2 specifies. So I released a new version of Module::Install::PrePAN. This is just a M::I extension. What I say in this article is about not only M::I related issues but also toolchans, I think.
Any suggestion how I should do with that things? I'll submit a proposal again to metacpan authors if it wouldn't a problem.
PostScript
I had been misunderstanding when I wrote this article that CPAN META Spec 2 is at draft status.
David and Ricardo Signes drafted the final version 2 spec in April 2010 based on the version 1.4 spec and patches contributed during the proposal process.
http://search.cpan.org/~dagolden/CPAN-Meta-2.112621/lib/CPAN/Meta/Spec.pm#CONTRIBUTORS
daxim taught me at #metacpan@irc.perl.org that "the spec is officially passed, "drafted" here is just a different word for "authored" or "have written"".