cdnjs is a free distributed JS library delivery service.
Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
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.
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.