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.INK;
    this.data.inkLists = [];
    const rawInkLists = parameters.dict.getArray("InkList");
    if (!Array.isArray(rawInkLists)) {
      return;
    }
    const xref = parameters.xref;
    for (let i = 0, ii = rawInkLists.length; i < ii; ++i) {
      
      
      
      
      this.data.inkLists.push([]);
      for (let j = 0, jj = rawInkLists[i].length; j < jj; j += 2) {
        this.data.inkLists[i].push({
          x: xref.fetchIfRef(rawInkLists[i][j]),
          y: xref.fetchIfRef(rawInkLists[i][j + 1]),
        });
      }
    }
  }
}
class HighlightAnnotation extends MarkupAnnotation {
  constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.HIGHLIGHT;
    const quadPoints = (this.data.quadPoints = getQuadPoints(