Flutter uses its own UI engine. It does not rely on any webview AFAIK.
By contrast, Flutter minimizes those abstractions, bypassing the system UI widget libraries in favor of its own widget set. The Dart code that paints Flutter’s visuals is compiled into native code, which uses Impeller for rendering. Impeller is shipped along with the application, allowing the developer to upgrade their app to stay updated with the latest performance improvements even if the phone hasn’t been updated with a new Android version. The same is true for Flutter on other native platforms, such as Windows or macOS.
Flutter uses its own UI engine. It does not rely on any webview AFAIK.
https://docs.flutter.dev/resources/architectural-overview#flutters-rendering-model