Credit to @stephenhawk8054 for this: https://github.com/uBlockOrigin/uBlock-issues/discussions/2714#discussioncomment-6959723
Google is adding #AttributionReporting to Chrome: https://developer.chrome.com/docs/privacy-sandbox/attribution-reporting/
This is another reason to #stopusingchrome. Google is an ad company, and they have made it abundantly clear that #Chrome is just another tool to further that goal.