code: function AttributesArray(elt) {
    NamedNodeMap.call(this, elt);
    for (var name in elt._attrsByQName) {
      this[name] = elt._attrsByQName[name];
    }
    for (var i = 0; i < elt._attrKeys.length; i++) {
      this[i] = elt._attrsByLName[elt._attrKeys[i]];
    }
  }
docs: The attributes property of an Element will be an instance of this class. This class is really just a dummy, though. It only defines a length property and an item() method. The AttrArrayProxy that defines the public API just uses the Element object itself.