docs: function parse_PtgFunc(blob, length, opts) {
  	var ptg = blob[blob.l] & 0x1F;
  	var type = (blob[blob.l] & 0x60)>>5;
  	blob.l += 1;
  	var iftab = blob.read_shift(opts && opts.biff <= 3 ? 1 : 2);
  	return [FtabArgc[iftab], Ftab[iftab], type];
  }