assistant is a personal app used only by its owner, Tal Damelin. It is not offered to anyone else.
With the owner's permission, assistant uses Google Drive access limited to files it creates itself (the drive.file scope). It uploads encrypted backup files to the owner's own Google Drive and reads them back only to restore or test a backup. It cannot see any other files in the Drive.
Backups are encrypted before they are uploaded. No data is sold, shared with third parties, or used for advertising. Nothing is collected from anyone other than the owner.
Access can be removed at any time at https://myaccount.google.com/permissions.
Questions: use the support email shown on the app's Google sign-in screen.