I work at hCaptcha so I can't speak to any particular arrangements. We provide data labeling services and use the captcha as a means to lower costs for annotate

I work at hCaptcha so I can't speak to any particular arrangements. We provide data labeling services and use the captcha as a means to lower costs for annotated datasets. To that end, we intend to open source most of our captcha stack and would be an obvious choice for any privacy-concerned company rolling their own captcha.