The spec for this action:
https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2111850
An example of a form using this action:
https://www2.illinois.gov/rev/forms/reg/Documents/reg-1-mr.pdf
return wrapper;
  }
  /**
   * Format the contents of the popup by adding newlines where necessary.
   *
   * @private
   * @param {Object<string, string>} contentsObj
   * @memberof PopupElement
   * @returns {HTMLParagraphElement}
   */
  _formatContents({ str, dir }) {
    const p = document.createElement("p");
    p.dir = dir;
    const lines = str.split(/(?:\r\n?|\n)/);
    for (let i = 0, ii = lines.length; i < ii; ++i) {
      const line = lines[i];
      p.appendChild(document.createTextNode(line));
      if (i < ii - 1) {
        p.appendChild(document.createElement("br"));
      }
    }
    return p;
  }
  /**
   * Toggle the visibility of the popup.
   *
   * @private
   * @memberof PopupElement
   */
  _toggle() {