docs: private boolean isDefaultFile(CmsResource resource) throws CmsException {
  
          CmsObject cms = getCmsObject();
          if (resource.isFolder()) {
              return false;
          }
  
          CmsResource parent = cms.readResource(
              CmsResource.getParentFolder(cms.getSitePath(resource)),
              CmsResourceFilter.ONLY_VISIBLE_NO_DELETED);
          CmsResource defaultFile = cms.readDefaultFile(parent, CmsResourceFilter.ONLY_VISIBLE_NO_DELETED);
          return resource.equals(defaultFile);
      }