The Puppet Development Kit (PDK) provides a unified approach and CLI tool to simplify Puppet module development. It allows users to easily bootstrap new modules, add Puppet code components like classes and types, migrate existing modules, and match local development workflows with automated CI/testing pipelines through commands like "pdk new module", "pdk validate", and "pdk test unit". The PDK aims to make Puppet and Ruby development tools more accessible and provides a simpler way to develop and test Puppet code.