Today’s Firefox 91 release adds new site-wide cookie-clearing action

Enlarge / This menacing firefox seems to be on the prowl for unwanted third-party cookies. (credit: Hung Chung Chih via Getty Images)

Mozilla’s Firefox 91, released this morning, includes a new privacy management feature called Enhanced Cookie Clearing. The new feature allows users to manage all cookies and locally stored data generated by a particular website—regardless of whether they’re cookies tagged to that site’s domain or cookies placed from that site but belonging to a third-party domain, eg Facebook or Google.

Building on Total Cookie Protection

Mozilla isn’t being delicate about which tech giant is first in its crosshairs. (credit: Mozilla)

The new feature builds and depends upon Total Cookie Protection, introduced in February with Firefox 86. Total Cookie Protection partitions cookies by the site that placed them, rather than the domain that owns them—which means that if a hypothetical third party we’ll call “Forkbook” places tracking (or authentication) cookies on both momscookies.com and grandmascookies.com, it can’t reliably tie the two together.

Without cookie partitioning, a single Forkbook cookie would contain the site data for both momscookies.com and grandmascookies.com. With cookie partitioning, Forkbook must set two separate cookies—one for each site—and can’t necessarily relate one to the other.