First party site isolation is more thorough than just blocking third party cookies: https://2019.www.torproject.org/projects/torbrowser/design/#identifier-linka

First party site isolation is more thorough than just blocking third party cookies: https://2019.www.torproject.org/projects/torbrowser/design/#identifier-linkability https://2019.www.torproject.org/projects/torbrowser/design/#... Basically, everything is isolated to the first party domain (the domain of the URL in the address bar), including content caches, HTTP/2 connections, local storage, preferences, etc.