For March I was assigned ExtUtils::Install which is used by ExtUtils::MakeMaker and Module::Build to install Perl modules. This is, by far, the most core module I have been assigned to date. I was impressed by it's long list of green test reports on CPAN testers for every version and system imaginable.
I read through the code and documentation and one thing stuck out like a sore thumb. Packlist.pm had a very different style than the rest of the code. It had little to no whitespace and it had a combination of tabs and spaces for indentation. My OCD forced me to fix this immediately.
I then looked at the CPANTS Kwalitee report and found some low hanging fruit in the form of a LICENSE file. I copied the copyright and license information from the README on github, and added the LICENSE file to the MANIFEST.
With that done, I submitted my March Pull request.
Update 3/26/15 - I updated my pull request so LICENSE contains the full license text. Thanks to the recommendation of App::Software::License from Karen Etheridge it was quick and easy.