A personal email and calendar assistant, run privately by one person.
Nova Assistant is a private tool that helps its owner manage his own Google accounts — triaging email, keeping subscriptions under control, and organising a calendar. It runs locally on the owner's own computer rather than as a hosted service, and it has exactly one user.
Nobody else. This is not a product, there is no sign-up, and no accounts other than the owner's own are connected to it. The page you are reading exists because Google requires a published home page and privacy policy for an application that requests access to Gmail and Calendar data.
What data the application touches and what happens to it is set out in full in the privacy policy.