code: @Nonnull
    public PDFObjectOptions setFallbackLink (@Nullable final String sText)
    {
      m_aFallbackLink = sText == null ? null : JSExpr.lit (sText);
      return this;
    }
docs: Any string entered here will be inserted into the target element when the
  browser doesn't support inline PDFs. HTML is supported. Use the shortcode
  <code>[url</code>] to insert the URL of the PDF (as specified via the URL
  parameter in the embed() method).
  
  @param sText
  Text to use
  @return this for chaining