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);
    this.data.annotationType = AnnotationType.POLYGON;
  }
}
class CaretAnnotation extends MarkupAnnotation {
  constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.CARET;
  }
}
class InkAnnotation extends MarkupAnnotation {