docs: public String getDefaultApp(Set<String> supportedApps) {
      String defaultApp = getAut();
      // if the launch activity is specified, just return.
      if (getLaunchActivity() != null) {
        return defaultApp;
      }
      // App version is not specified. Get the latest version from the apps store.
      if (!defaultApp.contains(":")) {
        return getDefaultVersion(supportedApps, defaultApp);
      }
      return supportedApps.contains(defaultApp) ? defaultApp : null;
    }