Does Firebase encrypt the token before saving it in AsyncStorage?

Question

I understand that for persistence login Firebase uses asyncstorage to store the token. What I don't understand is why as it's clearly mentioned that asyncstorage is not encrypted and should not be used for token storage: https://reactnative.dev/docs/security

export const auth = initializeAuth(app, {
  persistence: getReactNativePersistence(AsyncStorage),
});

Edit: I am using Firebase Javascript sdk https://firebase.google.com/docs/reference/js/auth.md#auth_package not RNfirebase