docs: private JSONObject getNodeConfig() {
      JSONObject res = new JSONObject();
      try {
        res.put("class", "org.openqa.grid.common.RegistrationRequest");
        res.put("configuration", getConfiguration());
        JSONArray caps = new JSONArray();
        JSONArray devices = driver.getSupportedDevices();
        for (int i = 0; i < devices.length(); i++) {
          JSONObject device = (JSONObject) devices.get(i);
          for (int x = 0; x < driver.getSupportedApps().length(); x++) {
            caps.put(getDeviceConfig(device, driver.getSupportedApps().getJSONObject(x)));
          }
        }
        res.put("capabilities", caps);
      } catch (JSONException e) {
        throw new SelendroidException(e.getMessage(), e);
      }
      return res;
    }