@lispi314@udongein.xyz Digging in the Anubis docs for some information, I found that there is also this non-PoW challenge:

The preact challenge sends the browser a simple challenge that makes it run very lightweight JavaScript that proves the client is able to execute client-side JavaScript. It uses Preact (a lightweight client side web framework in the vein of React) to do this.

What? Using “Fast 3kB alternative to React with the same modern API” (quoting the Preact NPM page) to test that the client can execute JavaScript? ​:blobfoxnotlikethis:​