code: public static String getStaticResourceVersion() {
          if (null == staticResourceVersion) {
              staticResourceVersion = getLatkeProperty("staticResourceVersion");
              if (null == staticResourceVersion) {
                  staticResourceVersion = String.valueOf(startupTimeMillis);
              }
          }
  
          return staticResourceVersion;
      }
docs: Gets static resource (JS, CSS files) version.
  <p>
  Returns the value of "staticResourceVersion" property in local.properties. Returns the
  {@link #startupTimeMillis application startup millisecond} if not found the "staticResourceVersion" property in
  local.properties.
  </p>
  
  @return static resource version