docs: @Nonnull
    public static IUserAgent decryptUserAgentString (@Nonnull final String sUserAgent)
    {
      ValueEnforcer.notNull (sUserAgent, "UserAgent");
  
      String sRealUserAgent = sUserAgent;
  
      // Check if surrounded with '"' or '''
      if (sRealUserAgent.length () >= 2)
      {
        final char cFirst = sRealUserAgent.charAt (0);
        if ((cFirst == '\'' || cFirst == '"') && StringHelper.getLastChar (sRealUserAgent) == cFirst)
          sRealUserAgent = sRealUserAgent.substring (1, sRealUserAgent.length () - 1);
      }
  
      // Skip a certain prefix that is known to occur frequently
      if (sRealUserAgent.startsWith (SKIP_PREFIX))
        sRealUserAgent = sRealUserAgent.substring (SKIP_PREFIX.length ());
  
      return new UserAgent (sRealUserAgent, _decryptUserAgent (sRealUserAgent));
    }