Protect Yourself From Meta’s Latest Attack on PrivacyIn-case you needed more evidence that Meta was evil... other articles explain on a technical level what they were doing. From what I understand, Meta's app for Android created a listener on localhost which Meta Javascript trackers on websites (infecting like 20%+ of websites on the clearnet) used to completely bypass any and all on-device privacy protections. Quote from the article:
"Even users who blocked or cleared cookies, hid their IP address with a VPN, or browsed in incognito mode could be identified"
Meta deleted the feature after the news article came out, they knew what they were doing was wrong. Rest assured the brilliant people who made this evil spyware are working hard on a workaround to get that valuable PII to sell to the highest bigger. Yandex got in trouble for doing the same thing (localhost tracker). This is from an EFF article with advice on how to kill this kind of thing.