docs: function getPlatformExtension(file, platforms = SUPPORTED_PLATFORM_EXTS) {
    const last = file.lastIndexOf('.');
    const secondToLast = file.lastIndexOf('.', last - 1);
    if (secondToLast === -1) {
      return null;
    }
    const platform = file.substring(secondToLast + 1, last);
    return platforms.has(platform) ? platform : null;
  }