> The popular Total Cookie Protection moves from the optional strict setting to always-on in private browsing. This feature maintains a separate “cookie jar” for each website you visit while browsing privately. Any time a site deposits a cookie, Firefox locks it up in its own cookie jar so that it can’t be shared with any other website.

Why isn't that on all the time, even in normal browsing mode? Like, what breaks because of that? I thought cookies were locked per-domain since the invention of cookies.