Apache is a free and open-source cross-platform web server software.
Debian is a Linux software which is a free open-source software.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Mod_perl is an optional module for the Apache HTTP server. It embeds a Perl interpreter into the Apache server. In addition to allowing Apache modules to be written in the Perl programming language, it allows the Apache web server to be dynamically configured by Perl programs.
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages.
PHP is a general-purpose scripting language used for web development.