Yes, all modern browsers divide their cache per-site. Some large advertising companies like Taboola have abused caches to store unique identifiers. I won't be s

Yes, all modern browsers divide their cache per-site. Some large advertising companies like Taboola have abused caches to store unique identifiers. I won't be shocked if Google and Facebook have also used this, so Safari (from 2013, https://bugs.webkit.org/show_bug.cgi?id=110269 https://bugs.webkit.org/show_bug.cgi?id=110269), Firefox (depending on settings from 2018 and widely deployed in 2020, https://developer.mozilla.org/en-US/docs/Web/Privacy/State_Partitioning https://developer.mozilla.org/en-US/docs/Web/Privacy/State_P...) and Chrome (from 2020, https://developer.chrome.com/blog/http-cache-partitioning/ https://developer.chrome.com/blog/http-cache-partitioning/) now separate caches.