The feature is based on "Client-Side Storage Partitioning," a new standard currently being developed by the World Wide Web Consortium's Privacy Community Group.
"Network Partitioning is highly technical, but to simplify it somewhat; your browser has many ways it can save data from websites, not just via cookies," privacy researcher Zach Edwards told
ZDNet in an interview this week.
"These other storage mechanisms include the HTTP cache, image cache, favicon cache, font cache, CORS-preflight cache, and a variety of other caches and storage mechanisms that can be used to track people across websites."
Edwards says all these data storage systems are shared among websites.