A package-based dependency manager for PHP projects. More information: https://getcomposer.org/.
composer.json file:composer init
composer.json:composer require user/package
composer.json and create composer.lock:composer install
composer.json and composer.lock:composer remove user/package
composer.json and note new versions in composer.lock file:composer update
composer.lock after updating composer.json manually:composer update --lock
composer why-not user/package
composer self-update