Attach (recommended) or Link to PDF file here:
PDF from #4106, https://mail.gnome.org/archives/evince-list/2013-November/pdfNC0hkVW67a.pdf.

Steps to reproduce the problem:
1. Open the PDF

What is the expected behavior?
![immagine](https://user-images.githubusercontent.com/1616846/121865567-67ca4200-ccfe-11eb-8673-1d6e863fc8d5.png)

What went wrong?
The PDF doesn't load, `TypeError: can't access property Symbol(), match is null` error is logged in the console.
if (this.w !== "" && this.h !== "") {
      bbox = [this.x, this.y, this.w, this.h];
    } else {
      const width = this.w === "" ? marginH + this[$extra].width : this.w;
      const height = this.h === "" ? marginV + this[$extra].height : this.h;
      bbox = [this.x, this.y, width, height];
    }
    delete this[$extra];
    return HTMLResult.success(createWrapper(this, html), bbox);
  }
}
class Execute extends XFAObject {
  constructor(attributes) {
    super(TEMPLATE_NS_ID, "execute");
    this.connection = attributes.connection || "";
    this.executeType = getStringOption(attributes.executeType, [
      "import",
      "remerge",
    ]);
    this.id = attributes.id || "";
    this.runAt = getStringOption(attributes.runAt, [
      "client",
      "both",
      "server",
    ]);
    this.use = attributes.use || "";
    this.usehref = attributes.usehref || "";
  }
}
class Extras extends XFAObject {