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.CIRCLE;
  }
}
class PolylineAnnotation extends MarkupAnnotation {
  constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.POLYLINE;
    this.data.vertices = [];
    
    
    
    const rawVertices = parameters.dict.getArray("Vertices");
    if (!Array.isArray(rawVertices)) {
      return;
    }
    for (let i = 0, ii = rawVertices.length; i < ii; i += 2) {
      this.data.vertices.push({
        x: rawVertices[i],
        y: rawVertices[i + 1],
      });
    }
  }
}
class PolygonAnnotation extends PolylineAnnotation {