The PHP team is once again proud to participate in the Google Summer of Code. Seven students will "flip bits instead of burgers" this summer: Mentored by Michael Wallner, Hannes Magnusson will work on LiveDocs, which is a "tool to display DocBook XML files in a web browser on the fly, without the need of building all HTML target files first". This project will be of great value to the PHP Documentation Team. The PHP Interpreter uses reference counting to keep track of which objects are no longer referenced and thus can be destroyed. A major weakness in the current implementation is that it cannot detect reference cycles, that is objects that reference each other in a circular graph structure which is not referenced itself from outside the circle. Mentored by Derick Rethans, David Wang will implement a new reference counting algorithm that will alleviate this problem. Xdebug provides a range of useful functionality for PHP developers, including detailed error information, code coverage and profiling support, and support for remote debugging using the GDB and DBGp protocols. Mentored by Xdebug's creator, Derick Rethans, Adam Harvey will develop a cross-platform GUI application that implements the DBGp protocol and allows PHP applications to be debugged using Xdebug in a development environment agnostic fashion. Mentored by Lukas Smith, Konsta Vesterinen will work on the object-relational mapper Doctrine. Mutation Testing, or Automated Error Seeding, is an approach where the testing tool makes some change to the tested code, runs the tests, and if the tests pass displays a message saying what it changed. This approach is different than code coverage analysis, because it can find code that is executed by the running of tests but not actually tested. Mentored by Sebastian Bergmann, Mike Lewis will implement Mutation Testing for PHPUnit. Mentored by Helgi Þormar Þorbjörnsson, Igor Feghali will add support for foreign keys to MDB2_Schema, a package that "enables users to maintain RDBMS independant schema files in XML that can be used to create, alter and drop database entities and insert data into a database". Mentored by David Coallier, Nicolas Bérard-Nault will refactor the internals of Jaws, a Framework and Content Management System for building dynamic web sites, for PHP 6.