It used to be that CSS leaked all visitor states with no user interaction. This was patched by browsers a few years back, but there are still ways to extract so

It used to be that CSS leaked all visitor states with no user interaction. This was patched by browsers a few years back, but there are still ways to extract some data from :visited, it just requires user interaction now. https://frantzmiccoli.github.io/visited-captcha-history/ https://frantzmiccoli.github.io/visited-captcha-history/