The biggest offenders were games like Minecraft, Hitman Sniper, Grand Theft Auto: San Andreas, Need For Speed: Most Wanted, Monument Valley, and more.
Social media apps also fared poorly in Mozilla's analysis. Facebook, Snapchat, and Twitter had the least accurate Play Store labels, while YouTube, Google Chrome, Gmail, WhatsApp, Instagram, TikTok, and Spotify did slightly better.
The Data Safety information on Google Play Store pages and the App Privacy details on Apple App Store pages are supposed to inform users about what information an app collects or shares. They say whether an app collects and shares contact information, location, email address, browsing history, search history, financial information, etc. Apple started its program in 2020, while Google followed suit in 2022.
The Washington Post checked Apple's labels in 2021 against what anti-surveillance software said the apps were sharing. The results showed that many iOS apps shared more than what their App Privacy details disclosed. Mozilla compares its study to the Post's report.
One of the biggest problems is that both tech giants trust developers to report what their apps share. Apple's App Store pages admit this in fine print, but Mozilla found that Android's Play Store doesn't. Mozilla recommends that both should disclose their honour systems in plain language.
The Firefox developer finds Google's definitions of "collection" and "sharing" too narrow, possibly letting developers deceive users. Mozilla prefers to avoid Google's exemption of anonymised data from label requirements due to doubts about whether data can be anonymised.
Mozilla checked 40 of the most popular Android apps and found discrepancies on 80 per cent of their Play Store pages compared to their privacy policies. The apps had different levels of contradiction, but 40 per cent (16 apps) had severe inconsistencies. Another 37.5 per cent (15 apps) had moderate discrepancies, and only 15 per cent (six apps) had little to no difference.