Sheets Sync
A private utility that keeps a Google Sheet up to date.
Sheets Sync signs in with a Google Account and reads and writes a single spreadsheet on that account's behalf. It runs on a private server operated by the owner of this domain. There is no public sign-up and no account to create.
Access it requests
One scope only — drive.file, which covers just the files opened with or created by this application. It cannot see the rest of your Drive, your mail, or your calendar.