I'm surprised they're allowed to listen on UDP ports, IIRC this requires special permissions?
> The Meta (Facebook) Pixel JavaScript, when loaded in an Android mobile web browser, transmits the first-party _fbp cookie using WebRTC to UDP ports 12580–12585 to any app on the device that is listening on those ports.
Borders on criminal behavior.
Apparently this was a European team of researchers, which would mean that Meta very likely breached the GDPR and ePrivacy Directive. Let's hope this gets very expensive for Meta.