On the PHPClasses.org site today Manuel Lemos has a new post showing how you can use Composer in your deployments to help install packages from the PHPClasses site.
You can install one or more packages from PHP Classes, JS Classes or other Composer repository sites. [...] To make it simpler for you, PHP Classes and JS Classes generate a sample composer.json file for each package available in the Composer repository. Just go in the page of the package you want to install and click on the Install with Composer link.
He includes a brief guide on installing Composer and an example of the resulting "composer.json" file when you click on a link in a package. He points out the use of logins (depends on the package maintainer) and the use of an "auth.json" to automatically provide this information.
This is a great example of how a site that puts the Composer ecosystem to work to provide packages outside of Packagist. Composer, by default, relies on Packagist for its package information, but you can provide alternate repositories too - including using something like Satis for local packages.