phpXplorer is an file management system and explorer that makes it possible to work on a remote file system through a Web browser. By default, it includes dialogs for editing HTML, PHP, images, Apache, compressed files, and emails. Its modular design makes it easy to build your own filetypes, property sheets, views, and themes. A permission manager allows you to restrict access to the shared file system for multiple users in a detailed way.
Kaolak is a Web-based community system. A Kaolak community is defined by its users and documents and forms a Kaolak branch. Kaolak is designed to handle many branches transparently from each other, within a single instance (one URL, one database). It features a permission scheme which allows users to give read/write access to documents they own to other groups/users. With a little PHP knowledge, modules can be implemented to extend Kaolak functionality.