[YmiYugy]

They don't really use browsers. They have basically build their own react-native version, but instead of using system UI as the backend they have a backend abstraction layer with implementations for their own rendering engine or alternatively a browser on platforms that don't support WebAssembly. They only use WebAssembly rather than native because updating native code typically requires an app update via the platforms update mechanism which is slow and unreliable. It looks like the new Rust UI version just swaps out their react fork for rust code and it looks like they are dropping browser support altogether.