code: function(doc, pb) {
  	// Effectively, skip applying data-parsoid.  Note that if we were to
  	// support a pb2html downgrade, we'd need to apply the full thing,
  	// but that would create complications where ids would be left behind.
  	// See the comment in around `DOMDataUtils.applyPageBundle`
  	DOMDataUtils.applyPageBundle(doc, { parsoid: { ids: {} }, mw: pb.mw });
  	// Now, modify the pagebundle to the expected form.  This is important
  	// since, at least in the serialization path, the original pb will be
  	// applied to the modified content and its presence could cause lost
  	// deletions.
  	pb.mw = { ids: {} };
  }
docs: Downgrade content from 999.x to 2.x.
  
  @param {Document} doc
  @param {Object} pb