If you have a Gmail account and have had it for a long time, think about how many purchases you have made online and in stores where receipts have been sent to your email address. Google has had a tool in place inside Gmail that keeps track of all the purchases ever made with receipts that came to Gmail all in one place.
The odd thing about this tool is that while Google told The Verge in a statement that the tool was meant to make it easier for users to keep track of all their purchases and subscriptions in one place, the tool was never publicized. Google pointed out that only you can see your purchase data and that the data can be deleted at any time. Users who have had a Gmail account for many years and made a lot of purchases where the info was sent to a Gmail address could have a huge number of purchases stored within the tool. And as you might imagine, this is a rather large privacy threat vector, waiting to exploited.
There is no way to delete all the purchases at once; you have to do it one purchase at a time. Google says that it doesn't use the data on what you purchase online to target ads. The search giant promised back in 2017 that it would stop using data collected via Gmail to personalize ads. The tool that gathers all the purchases isn't outright nefarious, according to reports, but it shines a light on how Google isn't always clear about its tools and the data it gathers on users.
It also raises the issue of third-party apps pulling data from Google and gaining access to your purchase history. Google has a history of collecting and sharing data about users without their express permission, such as supplementing ad-targeting tools with MasterCard purchase history to allow advertisers to tie ads served to real-world purchases. Those wanting to see the data that Google has about their purchases can use the tool here. Facebook has also had serious issues with user privacy and faces a potential FTC fine in the billions.