Safari blocks third-party cookies by default and introduced a new Storage Access SPI so third-party sites that do need cookies can request explicit user permission. This is all part of Safari’s Intelligent Tracking Protection.
Firefox doesn’t block third-party cookies by default because that can break sites that haven’t been updated to use the Storage Access API. Instead Firefox’s Enhanced Tracking Protection blocks cookies from a blocklist of known trackers and all other third-party cookies (e.g. new trackers or legitimate use cases) are isolated using Total Cookie Protection (which has the inconvenient acronym TCP).
Total Cookie Protection uses double-keyed cookie jars, so cookies from analytics.example included in an example.com page are placed in a separate cookie jar from analytics.example cookies included in an example.org page. This allows both sites to use the same third-party analytics service, but the analytics service sees different cookies for each site and can’t link the cookies to one user’s browsing behavior.
Firefox doesn’t block third-party cookies by default because that can break sites that haven’t been updated to use the Storage Access API. Instead Firefox’s Enhanced Tracking Protection blocks cookies from a blocklist of known trackers and all other third-party cookies (e.g. new trackers or legitimate use cases) are isolated using Total Cookie Protection (which has the inconvenient acronym TCP).
Total Cookie Protection uses double-keyed cookie jars, so cookies from analytics.example included in an example.com page are placed in a separate cookie jar from analytics.example cookies included in an example.org page. This allows both sites to use the same third-party analytics service, but the analytics service sees different cookies for each site and can’t link the cookies to one user’s browsing behavior.
https://blog.mozilla.org/en/products/firefox/firefox-rolls-o...