AOS Mailbox is a personal tool for its owner's own Gmail account. No one else uses it.
It reads message details (sender, subject, date, labels) to apply labels and move mail. It does not send or delete mail.
The data stays on the owner's computer. It is never shared, sold, or used for advertising.
Use of Google user data follows the Google API Services User Data Policy, including Limited Use.
Access can be revoked at myaccount.google.com/permissions.