building-rotavo-15.js

// connectedCallback()
if (!this._container.part) {
  // create a <span>
  const wrapper = document.createElement('span');
  // move this element's child nodes into it
  wrapper.append(...this.childNodes);
  // add the classes
  wrapper.classList.add('fallback');
  this.classList.add('fallback');
  // and add the wrapper into this element
  this.append(wrapper);
}