They do mention that subdomains can't be used for tracking in the introduction to Private Click Measurement [1] But I have to be honest that I can't quite wrap

They do mention that subdomains can't be used for tracking in the introduction to Private Click Measurement [1] But I have to be honest that I can't quite wrap my head around how this is supposed to work. 1. https://webkit.org/blog/11529/introducing-private-click-measurement-pcm/ https://webkit.org/blog/11529/introducing-private-click-meas...