dir/

     Makefile.PL
     Build.PL

     dist.ini


     README
     CHANGES
     MANIFEST
     MANIFEST.SKIP
     META.yml
     META.json

     lib/
        Application/Name.pm
        Application/Name/...
     script/
        application.pl

     t/
     xt/

     sample/

     share/
     templates/
     views/

The directory has a Makefile.PL, a Build.PL, or a dist.ini describing how to package the module.

Makefile.PL is used by ExtUtils::MakeMaker and by Module::Install

Build.PL is used by Module::Build which can optionally generate a Makefile.PL.

dist.ini is used by Dist::Zilla which then creates a Makefile.PL to be added to the distribution.

The README if just a description of what your distribution might do.

The CHANGES file includes the description of the changes between releases.

MANIFEST is the list of files that need to be included in the distribution. It is used for packaging and also to check if all the files were included in the distribution. In the directory tree there can be all kinds of temporary files that you don't want to include in the distribution. So you won't list them in the MANIFEST.

This file can be maintained manually or, alternatively, you can keep a file called MANIFEST.SKIP that lists the files that should not be included. Then during the packaging, you can generate the MANIFEST file based on what you have in the directory skipping the ones mentioned in the MANIFEST.SKIP. The advantage of using MANIFEST.SKIP is that it can include wildcards that will match a full set of files.

META.yml and META.json contain the same meta-information about the distribution in YAML and JSON format respectively. The information includes the dependencies, the information about the author, version numbers, etc. They are generated during the packaging process.

The modules go into the lib/ directory.

If there are scripts distributed they are usually placed in the script/ subdirectory.

The unit-test files are located in the t/ directory and have .t extension.

xt/ can hold additional test scripts that should be executed only by the author/maintainer of this distribution, but not by the people who install it.

There can also be a directory called sample/ or examples/ or eg/ to hold examples scripts.

There can be addition directories such as share/, templates/, views/, public/ depending on the application you are writing and distributing.

Form all these files, at the end only the content of the lib/ directory and the script/ directory will be installed. In addition you can tell Perl to install some of the extra files if they are need for your application.