When FPI is enabled, the ad tracking tool can not see all the cookies it has posted on that user's PC, but only the cookie created for the domain that the user is viewing.
![Arrow :arrow:](./images/smilies/icon_arrow.gif)
- https://www.ghacks.net/2017/11/22/how-t ... n-firefox/
- https://www.bleepingcomputer.com/news/s ... isolation/
/!\ This feature is not enabled by default because it can cause some user login persistence issues.