"use strict";
  const SymbolTree = require("symbol-tree");
  
  exports.cloningSteps = Symbol("cloning steps");
  
  // TODO: the many underscore-prefixed hooks should move here
  // E.g. _attrModified (which maybe should be split into its per-spec variants)
  
  /**
   * This SymbolTree is used to build the tree for all Node in a document
   */
  exports.domSymbolTree = new SymbolTree("DOM SymbolTree");