cdnjs is a free distributed JS library delivery service.
Emotion is a library designed for writing CSS styles with JavaScript.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
Unpkg is a content delivery network for everything on npm.
Vercel is a cloud platform for static frontends and serverless functions.