<model-viewer> is an open-source web component developed by Google and maintained through GitHub. <model-viewer> aims at putting 3D content on the web easily with a few lines of HTML code. This was first introduced with Chrome 72 in July 2019 and enables users to view 3D in the browser and mobile devices.
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.
Varnish is a reverse caching proxy.