Use Cap instead of hCAPTCHA (for the flagship instance)

It's selfhostable.

That wasn't really my question.

I only know of small personal sites but yeah with "only" 7k stars it's still relatively unpopular edit: see below comment (Adguard, Bunny, Fraunhofer)

GitHub stars aren't an accurate metric of popularity tbh. It's like Facebook likes back in the day, you can get a lot of them but only have 3 people know about your product. Judging by their site (https://trycap.dev/), Adguard (for their temp mail product), Bunny (EU CDN, see them as yuropean Cloudflare alternative) and Fraunhofer (German research organization) all use some form of Cap, be it heavily modified or not so there is/was some big companies reliance. I would bet it would be more but companies don't usually publicly endorse things out of their goodwill, they yoink and think later.

Good points, thanks. idk how I forgot about the brands listed on their site lol. On GitHub stars, I think an unpopular thing can have lots of stars but a popular thing usually does have lots of stars. So I'm saying it can't be too popular relative to other captchas.

In any case, it still could be a nice addition.

I have, https://github.com/altcha-org/altcha is better IMO. Both are good/fine. hcaptcha and recaptcha are extremely easy to bypass, but also being ran by the big corps we're here to move away from.