Apache is a free and open-source cross-platform web server software.
Debian is a Linux software which is a free open-source software.
Mod_dav is an Apache module to provide WebDAV capabilities for your Apache web server. It is an open-source module, provided under an Apache-style license.
Mod_jk is an Apache module used to connect the Tomcat servlet container with web servers such as Apache, iPlanet, Sun ONE (formerly Netscape) and even IIS using the Apache JServ Protocol. A web server waits for client HTTP requests.
PHP is a general-purpose scripting language used for web development.
TYPO3 is a free and open-source Web content management system written in PHP.