HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Issuu is a digital discovery and publishing platform.
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.
Trusted Shops is a company that acts as a 3'rd party representing the common interests of both consumers and retailers.
Varnish is a reverse caching proxy.