Cloudflare Browser Insights is a tool that measures the performance of websites from the perspective of users.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Varnish is a reverse caching proxy.