How to minify a batch of PHP files (psr-4)?

Question

PHP

Let's say there is a package on GitHub (psr-4) that is intended to be installed via composer., is it really possible to compress everything into 1 file in order to include it via require?
1. We write the library in its normal form
2. We convert it into a single file
3. We use it in ancient CMS
Maybe someone has come across such tools?

Answer 1

composer require smartinus44/phpfilemerger
https://github.com/smartinus44/phpfilemerger

Answer 2

There is such a thing on packagist , maybe there is a fresher one, but I could not find it