applications – Is the installation of the Brasil TV New app from outside of the App Store safe?

The only source for all iOS apps is the Apple Store, [other than some esoteric uses if you are an app developer distributing to a select group].

Unless your phone is jailbroken, then you cannot install any app from any other source.

If your app is not on the App Store at all, then to all intents & purposes it doesn’t exist for iOS.