[cyral]

That's one. Just look at some of the specs that have to be implemented. There are so many most devs have probably never even heard of. It's really mind boggling the amount of work required to create a full browser from scratch.

List of web APIs: https://developer.mozilla.org/en-US/docs/Web/API Canvas API spec: https://html.spec.whatwg.org/multipage/canvas.html

Take one look at the docs for just rendering text and any sane developer would probably give up: https://www.w3.org/TR/css-text-3/