HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
Material Design Lite is a library of components for web developers.
MkDocs is a static site generator, used for building project documentation.
Polyfill is a service which accepts a request for a set of browser features and returns only the polyfills that are needed by the requesting browser.