Why do you need access to my Google Drive?

This level of authorization is required to attach files to any new events in order to process it through our API call.

We can only access files we upload to Drive to attach to your events. We are limited to reading only those files and can not read anything else. We are requesting the https://www.googleapis.com/auth/drive.file which is described by Google here.

We tried to find a way to offer the Drive scope that would let users opt-in to using it. However, all of the answers currently available require more than one application and more powerful scopes. This was the only answer that didn’t add significant complexity, and while we wanted to offer a more nuanced approach, we have had to resort to asking all users for a single scope regardless of their intent to use attachments. This is a restriction of Google marketplace applications only being allowed one set of scopes, all of which are required.