In file https://github.com/mozilla/pdf.js/files/5249872/product1.pdf, the fifth text widget has a default appearance using font F1 and this one is neither in DR nor in AcroForm but in AP::N::Resources.
constructor(parameters) {
    super(parameters);
    const dict = parameters.dict;
    if (dict.has("IRT")) {
      const rawIRT = dict.getRaw("IRT");
      this.data.inReplyTo = isRef(rawIRT) ? rawIRT.toString() : null;
      const rt = dict.get("RT");
      this.data.replyType = isName(rt) ? rt.name : AnnotationReplyType.REPLY;
    }
    if (this.data.replyType === AnnotationReplyType.GROUP) {
      
      
      const parent = dict.get("IRT");
      this.data.title = stringToPDFString(parent.get("T") || "");
      this.setContents(parent.get("Contents"));
      this.data.contents = this.contents;
      if (!parent.has("CreationDate")) {
        this.data.creationDate = null;
      } else {
        this.setCreationDate(parent.get("CreationDate"));
        this.data.creationDate = this.creationDate;
      }
      if (!parent.has("M")) {
        this.data.modificationDate = null;
      } else {
        this.setModificationDate(parent.get("M"));