Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.