Tracking prevention is designed to protect you from being tracked by websites that you aren’t accessing directly. Whenever a website is visited, trackers from other sites may save information in the browser using cookies and other storage mechanisms. This information may include the sites you’ve visited and the content you’re interested in, building a digital profile which can be accessed by organizations to offer personalized content when visiting other sites.
The implementation in Microsoft Edge Insider preview builds is early and is likely to change as we hear from our customers and continue to test the feature. For that reason, it’s currently behind an experimental flag and disabled by default.