code: function parse_ExtProp(blob/*::, length*/)/*:Array<any>*/ {
  	var extType = blob.read_shift(2);
  	var cb = blob.read_shift(2) - 4;
  	var o = [extType];
  	switch(extType) {
  		case 0x04: case 0x05: case 0x07: case 0x08:
  		case 0x09: case 0x0A: case 0x0B: case 0x0D:
  			o[1] = parse_FullColorExt(blob, cb); break;
  		case 0x06: o[1] = parse_XFExtGradient(blob, cb); break;
  		case 0x0E: case 0x0F: o[1] = blob.read_shift(cb === 1 ? 1 : 2); break;
  		default: throw new Error("Unrecognized ExtProp type: " + extType + " " + cb);
  	}
  	return o;
  }
docs: /* [MS-XLS] 2.5.108