The Drupal Composer Project provides a scaffold for starting a new Drupal project and managing that project's dependencies with Composer. It was created before the drupal/recommended-project Composer project template was developed, which is the current best practice method for creating a new Drupal site with Composer.

A module is a set of PHP, JavaScript, and/or CSS files that extends site features and adds functionality. The Drupal core software comes with a set of modules that provide a range of features.

Object-oriented PHP utilizes classes and objects to organize code into reusable chunks. This approach helps us organize complex applications, such as Drupal, into modular code called classes that can be reused across the entire system.