The report also includes information about websites accessed by those apps or domains contacted by the apps. The domain information is helpful to detect websites that collect data across different websites and apps. The report separately tracks App Network activity and Website Network activity in addition to the most contacted domains. The last-mentioned activity takes place either through in-app web content or directly.

The App Privacy Report excludes network activity from private browsing sessions in browser apps. However, the network activities of some non-browser apps that deliver private modes are part of the part.
https://www.ihqreviews.com/2022/02/24/ios-15-app-privacy-report-what-it-contains-and-how-it-helps-to-enhance-your-privacy/