I'm a bit confused by the about and usage page. Is this natively supported in Blink and you need the Javascript to polyfill other browsers, or do you always need their JS library to use this type of CSS?
I think only the other browsers need a polyfill. I just opened the dev console in Chromium and started typing `CSS.paintWorklet` (part of the proposed CSS Paint API) and it's available.
Yes. Houdini lets you paint a layer via JavaScript. The only link with CSS is that you call the Houdini module from CSS and pass some properties.