Supercookies don't use local storage as regular cookies do. Instead, they are injected at the network level as Unique Identifier Headers (UIDH).

Supercookies are inserted by your Internet Service Provider (ISP) rather than the website itself.

Apple updated its browsers to prevent the use of supercookies in 2019. Google rolled out a similar fix late last year with the Chrome 86 release, an update that also rolled over into Microsoft's Chromium-based Edge browser. In January, Mozilla launched Firefox 85 which cracks down on supercookie-based tracking methods.10 Feb 2021