Add a Changelog (best named 'Changes') to the distribution. It should list at least major changes implemented in newer versions.
Add a section called "LICENSE" to the documentation, or add a file named LICENSE to the distribution.
Add =head1 LICENSE and the text of the license to the main module in your code.
Provide a short description in the NAME section of the pod (after the module name followed by a hyphen) at least for the main module of this distribution.
Remove the POD errors. You can check for POD errors automatically by including Test::Pod to your test suite.
Error: OPC-0.01/lib/OPC.pm -- Around line 19: =pod directives shouldn't be over one line long! Ignoring all 5 lines of content
Add =head1 LICENSE and/or the proper text of the well-known license to the main module in your code.
Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.
Add a 'repository' resource to the META.yml via 'meta_add' accessor (for Module::Build) or META_ADD parameter (for ExtUtils::MakeMaker).
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.