Composer is a tool for dependency management in PHP. It allows you to declare the libraries your project depends on and it will manage (install/update) them for you.
Please refer to the official Composer documentation for usage details.
From the host via fin:
fin composer --version
From with the cli container (fin bash) composer can be called directly:
composer --version
Unless the --working-dir= is used, the composer command must be run within the directory or child directory containing the
project’s composer.json file.