code: public static SelendroidResponse forCatchAllError(String sessionId, Throwable e) {
      try {
        return new SelendroidResponse(sessionId, StatusCode.UNKNOWN_ERROR.getCode(), e, CATCH_ALL_ERROR_MESSAGE_PREFIX);
      } catch (JSONException err) {
        return new SelendroidResponse(sessionId, StatusCode.UNKNOWN_ERROR.getCode());
      }
    }
docs: It is currently hard to detect whether a test failed because of a legitimate
  error by a developer or because something is going wrong in selendroid
  internals. This response marks error responses from the server that indicate
  something has gone wrong in the internals of selendroid.