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.
Google Font API is a web service that supports open-source font files that can be used on your web designs.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Varnish is a reverse caching proxy.