One such extension, https://www.tuxlervpn.com/faq/:

> Will other users of tuxlerVPN be able to connect using my IP address?

"When you use our free residential VPN, you automatically agree to add your IP address into the community pool. This means that you are trading your own IP address in return for the ability to connect via the IP addresses of other users. You can opt out of this by purchasing our premium subscription; once you upgrade to the premium version, your IP address will be removed from our community pool."

I mean, most “residential proxy” providers are selling access to hacked devices, or sneaky plugins

https://medium.com/@xianghangmi/resident-evil-understanding-...

Technical paper: https://ieeexplore.ieee.org/document/8835239