The Symfony PHP framework
Mockery is a simple yet flexible PHP mock object framework for use in unit testing with PHPUnit, PHPSpec or any other testing framework. Its core goal is to offer a test double framework with a succinct API capable of clearly defining all possible object operations and interactions using a human readable Domain Specific Language (DSL).
Bolt is a simple CMS written in PHP. It is based on Silex and Symfony components, uses Twig and either SQLite, MySQL or PostgreSQL.
The FrameworkBundle defines the main framework configuration, from sessions and translations to forms, validation, routing and more.
Open Source Point of Sale is a web based point of sale application written in PHP using CodeIgniter framework. It uses MySQL as the data back end and has a Bootstrap 3 based user interface.
The "Symfony Standard Edition" distribution
Asynchronous server-side framework for network applications implemented in PHP using libevent
Humbug is a Mutation Testing framework for PHP to measure the real effectiveness of your test suites and assist in their improvement. It eats Code Coverage for breakfast.
Barcode generator in PHP that is easy to use, non-bloated and framework independent.