Is it safe to allow installing from unknown sources
As a rule, when downloading RuStore on a smartphone, you’ll be warned from installing apps from unknown sources.
The fact is that devices with official firmware define only their predefined stores (Google Play, AppGallery) and manufacturers' stores (Samsung, Xiaomi and others) as reliable sources. Therefore, any unknown source is considered unreliable.
By installing the application from the official RuStore website, you actually risk nothing. The application is completely safe for all Android devices.