Apache is a free and open-source cross-platform web server software.
Calendly is an app for scheduling appointments, meetings, and events.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Next.js is a React framework for developing single page Javascript applications.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.