Apache Traffic Server is an open-source caching and proxying server that serves as an HTTP/1.1 and HTTP/2 reverse proxy with caching capabilities, load balancing, request routing, SSL termination, and support for advanced HTTP features.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Twenty Eleven is the default WordPress theme for 2011.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.
Yoast SEO is a search engine optimisation plugin for WordPress and other platforms.