The article mentions it was because their Firebase database was unsecured - meaning anyone who knew the url could get access to all the data. That was the defau

The article mentions it was because their Firebase database was unsecured - meaning anyone who knew the url could get access to all the data. That was the default for a long time, and Firebase will send you email reminders if you keep it unsecured. The developer ignored the best practices mentioned in the Firebase documentation and the email reminders that come out once a week (I think).