cdnjs is a free distributed JS library delivery service.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
Three.js is a cross-browser JavaScript library and application programming interface used to create and display animated 3D computer graphics in a web browser using WebGL.