[NooneAtAll3]

I don't understand the live demo

it gave me some ID, but how do I test that some different website can track me resulting in same ID?

or is it only "detect private browsing/container on same browser" kind of stuff?

[degamad]

The "supercookie" phenomenon from a few years ago (when this was created) was that despite using private browsing or deleting cookies, the site id remains the same for the same browser.

[mmooss]

It could track you between site visits, at a minimum.