FauxClockNG (package com.faux123.fauxclockng) by faux123.
FauxClockNG has no account. The developer's server holds data about you only if you bought Pro or turned on benchmark sharing.
GPA.What is deleted: the order number, the Google Play purchase token, and the device hash that the licence server stored for your purchase.
What is kept: nothing on the developer's server. Google keeps its own record of your purchase under Google's privacy policy. Deleting the record does not refund the purchase. If you later tap Restore purchase in the app, the server creates a new record.
The app then asks the server to delete what you uploaded. Nothing is kept.
Profiles, settings, statistics, and kernel backups stay on your device. To remove them, uninstall the app or clear its storage in Android settings.