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
print: event.detail.print,
        });
      },
      hidden: event => {
        event.target.style.visibility = event.detail.hidden
          ? "hidden"
          : "visible";
        this.annotationStorage.setValue(this.data.id, {
          hidden: event.detail.hidden,
        });
      },
      focus: event => {
        setTimeout(() => event.target.focus({ preventScroll: false }), 0);
      },
      userName: event => {
        
        event.target.title = event.detail.userName;
      },
      readonly: event => {
        if (event.detail.readonly) {
          event.target.setAttribute("readonly", "");
        } else {
          event.target.removeAttribute("readonly");
        }
      },
      required: event => {
        if (event.detail.required) {
          event.target.setAttribute("required", "");
        } else {
          event.target.removeAttribute("required");