packagist.org
In short: Packagist (packagist.org) accepts composer package listing. It is free to submit, takes only a few minutes, and scores 86/100 on our impact ranking (high impact).
Publish an installable PHP package in a public repository and submit its composer.json with homepage and support links.
Only genuine Composer packages are suitable; keep releases and package metadata maintained.
Priority is high, which sets the band. It is free and quick to complete, which adjusts it within that band. The score ranks your queue — it is not a measure of domain authority.