Apache is a free and open-source cross-platform web server software.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OpenSSL is a software library for applications that secure communications over computer networks against eavesdropping or need to identify the party at the other end.
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.