docs: function parse_ExternName(blob, length, opts) {
  	var flags = blob.read_shift(2);
  	var body;
  	var o = ({
  		fBuiltIn: flags & 0x01,
  		fWantAdvise: (flags >>> 1) & 0x01,
  		fWantPict: (flags >>> 2) & 0x01,
  		fOle: (flags >>> 3) & 0x01,
  		fOleLink: (flags >>> 4) & 0x01,
  		cf: (flags >>> 5) & 0x3FF,
  		fIcon: flags >>> 15 & 0x01
  	});
  	if(opts.sbcch === 0x3A01) body = parse_AddinUdf(blob, length-2, opts);
  	//else throw new Error("unsupported SupBook cch: " + opts.sbcch);
  	o.body = body || blob.read_shift(length-2);
  	if(typeof body === "string") o.Name = body;
  	return o;
  }