Since Google is saving a history of what you purchase from third party merchants by scraping invoices and receipts sent to you through your Gmail account, it's safe to say that they are scanning your emails.
Google scans all photos in the cloud (Gmail, Drive, Google Photos) for CSAM and has for a long time. It just doesn't show contextual ads against email anymore, since those all sucked.
Since Google is saving a history of what you purchase from third party merchants by scraping invoices and receipts sent to you through your Gmail account, it's safe to say that they are scanning your emails.
https://news.ycombinator.com/item?id=26248486