https://en.wikipedia.org/wiki/Firebase
Firebase is a platform developed by Google for creating mobile and web applications. It was originally an independent company founded in 2011. In 2014, Google acquired the platform and it is now their flagship offering for app development. History. Firebase evolved from Envolve, a prior startup founded by James Tamplin and Andrew Lee in 2011.
Google Cloud + Firebase. Firebase projects are backed by Google Cloud, letting you scale your app to billions of users. Read more Trusted by the largest apps and games. Development teams around the world—including NPR, Halfbrick, Duolingo, and Venmo—use Firebase to ship their apps.
Well. What do you expect when you use a service that are based in USA, have closed their source code (or have they re-opened it again?), are using mainly Google as a server provider, and have zero privacy regarding your phone number (which are visible for everyone who see you within the app and you can’t do anything about it… today)?