Apache is a free and open-source cross-platform web server software.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
LazySizes unveilhooks plugin extends lazySizes to lazyload scripts/widgets, background images, styles and video/audio elements.
Open Graph is a protocol that is used to integrate any web page into the social graph.