Firefox 86 (新推出的 standard 版本) 推出了 Total Cookie Protection：「Firefox 86 Introduces Total Cookie Protection」。
每個站的 cookie 都有獨立的空間：
Our new feature, Total Cookie Protection, works by maintaining a separate “cookie jar” for each website you visit. Any time a website, or third-party content embedded in a website, deposits a cookie in your browser, that cookie is confined to the cookie jar assigned to that website, such that it is not allowed to be shared with any other website.
然後對於需要跨站類的應用另外處理，像是 3rd-party login：
In addition, Total Cookie Protection makes a limited exception for cross-site cookies when they are needed for non-tracking purposes, such as those used by popular third-party login providers. Only when Total Cookie Protection detects that you intend to use a provider, will it give that provider permission to use a cross-site cookie specifically for the site you’re currently visiting. Such momentary exceptions allow for strong privacy protection without affecting your browsing experience.
這樣的確把 cookie 的追蹤能力壓低很多，不過應該也會有不少站台掛掉...