Fastly is a cloud computing services provider. Fastly's cloud platform provides a content delivery network, Internet security services, load balancing, and video & streaming services.
GitHub Pages is a static site hosting service.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Math.js a JavaScript library that provides a comprehensive set of mathematical functions and capabilities for performing complex calculations and operations in web applications.
Varnish is a reverse caching proxy.