Module::Build is a system for building, testing, and installing Perl modules; it used to be part of Perl itself until version 5.22, which dropped it. It is meant to be an alternative to ExtUtils::MakeMaker. Developers may alter the behavior of the module through subclassing in a much more straightforward way than with MakeMaker. It also does not require a make on your system---most of the Module::Build code is pure-Perl.

Hash::Merge merges two arbitrarily deep hashes into a single hash. That is, at any level, it will add non-conflicting key-value pairs from one hash to the other, and follows a set of specific rules when there are key value conflicts. The hash is followed recursively, so that deeply nested hashes that are at the same level will be merged when the parent hashes are merged.

Sub::Quote provides an efficient generation of subroutines via string eval.

A CPAN::Meta::Requirements object models a set of version constraints like those specified in the META.yml or META.json files in CPAN distributions, and as defined by CPAN::Meta::Spec. It can be built up by adding more and more constraints, and will reduce them to the simplest representation.

The Digest::MD5 module allows you to use the MD5 Message Digest algorithm from within Perl programs. The algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input.

Similar to List::MoreUtils, Hash::MoreUtils contains trivial but commonly-used functionality for hashes. The primary focus for the moment is providing a common API - speeding up by XS is far away at the moment.

The functions exported by this module allow you to open URLs in the user's browser. A set of known commands per OS-name is tested for presence, and the first one found is executed. With an optional parameter, all known commands are checked.

Devel::Cycle This is a tool for finding circular references in objects and other types of references. Because of Perl's reference-count based memory management, circular references will cause memory leaks.

Authen-Passphrase is the base class for a system of objects that encapsulate passphrases. An object of this type is a passphrase recogniser; its job is to recognise whether an offered passphrase is the right one. For security such passphrase recognisers usually do not themselves know the passphrase they are looking for; they can merely recognise it when they see it. There are many schemes in use to achieve this effect and the intent of this class is to provide a consistent interface to them all. In addition to the base class, this module also contains implementations of several specific passphrase schemes.

This package provides encodings for JIS X 0212, which is also known as JIS 2000.

PPIx::Utilities is a collection of functions for dealing with PPI objects, many of which originated in Perl::Critic. They are organized into modules by the kind of PPI class they relate to, by replacing the "PPI" at the front of the module name with "PPIx::Utilities", e.g. functionality related to PPI::Nodes is in PPIx::Utilities::Node.

Math::Round provides functions to round numbers, both positive and negative, in various ways.

Loading MooX::StrictConstructor makes your constructors "strict". If your constructor is called with an attribute init argument that your class does not declare, then it dies.

Clipboard provides functionality to copy and paste with any OS.

IO::All combines all of the best Perl IO modules into a single nifty object oriented interface to greatly simplify your everyday Perl IO idioms. It exports a single function called io, which returns a new IO::All object. And that object can do it all!

File locking in Perl is usually done using the flock function. Unfortunately, this only allows locks on whole files and is often implemented in terms of the flock(2) system function which has some shortcomings (especially concerning locks on remotely mounted file systems) and slightly different behaviour than fcntl(2).

Manipulating stashes (Perl's symbol tables) is occasionally necessary, but incredibly messy, and easy to get wrong. This module hides all of that behind a simple API.

This module provides a small, fast utility for working with file paths.

This module uses Pod::Simple to convert POD to Markdown.

PPI::XS provides (minor) XS acceleration for PPI.

The package provides Perl bindings to OpenGL, GLU and FreeGLUT.

Sys::SigAction is a Perl extension for Consistent Signal Handling.

This is a library for generating letters, building HTML pages, or filling in templates generally. A template is a piece of text that has little Perl programs embedded in it here and there. When you fill in a template, you evaluate the little programs and replace them with their values.

This module provides $CWD and @CWD as alternatives to chdir().