code: public boolean isAssetFile(File path) {
          boolean isAsset = false;
  
          try {
              if(FileUtil.directoryOnlyIfNotIgnored(path.getParentFile())) {
                  if (FileUtil.isFileInDirectory(path, config.getAssetFolder())) {
                      isAsset = true;
                  } else if (FileUtil.isFileInDirectory(path, config.getContentFolder())
                      && FileUtil.getNotContentFileFilter().accept(path)) {
                      isAsset = true;
                  }
              }
          } catch (IOException ioe) {
              LOGGER.error("Unable to determine the path to asset file {}", path.getPath(), ioe);
          }
          return isAsset;
      }
docs: Determine if a given file is an asset file.
  @param path to the file to validate.
  @return true if the path provided points to a file in the asset folder.