docs: private String getUsernameForUserId(int id) {
          if (id > 0) {
              String username = userIdentityStore.getPortalUserName(id);
              if (username != null) {
                  return username;
              }
              logger.warn(
                      "Invalid userID {} found when exporting a portlet; return system username instead",
                      id);
          }
          return systemUsername;
      }