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.
bufferNew.push("\nendstream\nendobj\n");
    return [
      
      
      { ref: this.ref, data: bufferOriginal.join(""), xfa },
      
      { ref: newRef, data: bufferNew.join(""), xfa: null },
    ];
  }
  async _getAppearance(evaluator, task, annotationStorage) {
    this._fontName = null;
    const isPassword = this.hasFieldFlag(AnnotationFieldFlag.PASSWORD);
    if (!annotationStorage || isPassword) {
      return null;
    }
    const value =
      annotationStorage[this.data.id] && annotationStorage[this.data.id].value;
    if (value === undefined) {
      
      return null;
    }
    if (value === "") {
      
      return "";
    }
    const defaultPadding = 2;
    const hPadding = defaultPadding;
    const totalHeight = this.data.rect[3] - this.data.rect[1];
    const totalWidth = this.data.rect[2] - this.data.rect[0];
    if (!this.data.defaultAppearance) {