That worked in the early days of ITP, but it doesn't work anymore in any browser...

easrng · on June 2, 2021

It still works, I made a PoC and tested it and it works on Chromium, FireFox and MobileSafari. https://xsid-demo.glitch.me/

jefftk · on June 2, 2021

You're right, sorry, that does work! I definitely thought it didn't...

This seems worth raising with browsers as a bug, since this should be easily detectable as an attempt to work around cross-site tracking restrictions?