cdnjs is a free distributed JS library delivery service.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
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.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Unpkg is a content delivery network for everything on npm.