This document discusses version control and dependency management in PHP projects. It describes how version control systems like Subversion can be used to manage dependencies through svn:externals, but that this approach has limitations. It also outlines other approaches used in other languages like Make, Maven, and Pyrus, but notes that currently Phing lacks direct support for Pyrus, making dependency management in PHP projects challenging. The document provides resources for further information on tools like Phing, Pear, Pyrus, and others that could help address this issue.