This site identifies the application Nabanita, a personal assistant tool run privately by its operator, Abhishek Chowdhury. It is not a public product and has no accounts to sign up for.
The application connects to the operator's own Google Drive account, with the operator's permission obtained through Google's standard sign-in flow. It uses that access to find and read the operator's own documents when the operator asks it to — for example, to retrieve a file, or to work from documents already in his Drive.
The application's privacy policy explains exactly what is stored, what is not, and how to revoke access: Privacy policy.
Terms of use: Terms.