Total Cookie Protection is already on by default in private browsing mode, or strict ETP. Also Firefox Focus on Android. It's being rolled out to everyone in the standard ETP mode now.
It's currently controlled by setting `network.cookie.cookieBehavior` to `5`. (There is also a similar setting for private browsing mode which is already 5 by default).
It's currently controlled by setting `network.cookie.cookieBehavior` to `5`. (There is also a similar setting for private browsing mode which is already 5 by default).