[dizhn]

Awesome. I didn't see much detail about how it works in the page. Something like this would be useful for other sites as well. Is this using an existing technology?

(Firefox extension is not found. It's probably not in the store yet. Can't find with search either.)

[freediver]

We didn't launch this yet. It is in testing which is why we published this doc for testers. Full blog post with complete run down of the tech and implementation coming (very) soon.

[promiseofbeans]

Looks like they're implementing this, which is also used by Cloudflare Turnstile: https://privacypass.github.io/

The standard has also been published as RFC9578: https://www.rfc-editor.org/rfc/rfc9578.html