From Fedora Project Wiki
- php-packagist(xxx) vs php-composer(xxx)
As dicussed on IRC, I choose php-packagist which is only 1 composer repo (mostly the only one really used) for simplicity. Using "php-composer" will imply to also define the repository, so php-composer(repo/vendor/library), ex php-composer(packagist/fabpot/goutte).