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.
The lite-youtube-embed technique renders the YouTube video inside the IFRAME tag only when the play button in clicked thus improving the core web vitals score of your website.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Unpkg is a content delivery network for everything on npm.
Varnish is a reverse caching proxy.