I think the warped text ones have been phased out, but AFAIK it's in favor of the ones people mentioned above and some black magic for detecting humans without

I think the warped text ones have been phased out, but AFAIK it's in favor of the ones people mentioned above and some black magic for detecting humans without needing to click things. (I work for Google, on nothing related to browsers or recaptcha, this is purely my impression from encountering it logged in and out.)