docs: private String getRfsName(File file, String vfsName) {
  
          CmsStaticExportManager manager = OpenCms.getStaticExportManager();
          String filePath = file.getAbsolutePath();
          String result = CmsFileUtil.normalizePath(
              manager.getRfsPrefix(vfsName)
                  + filePath.substring(OpenCms.getStaticExportManager().getExportPath(vfsName).length()));
          return CmsStringUtil.substitute(result, new String(new char[] {File.separatorChar}), "/");
      }