HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Varnish is a reverse caching proxy.
W3 Total Cache (W3TC) improves the SEO and increases website performance and reducing load times by leveraging features like content delivery network (CDN) integration and the latest best practices.
WooCommerce is an open-source ecommerce plugin for WordPress.
WPML plugin makes it possible to build and run fully multilingual WordPress sites.
Yoast SEO is a search engine optimisation plugin for WordPress and other platforms.