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.
return this.contentType === "text/html";
  }
  [$onChild](child) {
    if (
      this.contentType === "text/html" &&
      child[$namespaceId] === NamespaceIds.xhtml.id
    ) {
      this[$content] = child;
      return true;
    }
    if (this.contentType === "text/xml") {
      this[$content] = child;
      return true;
    }
    return false;
  }
  [$toHTML](availableSpace) {
    if (this.contentType !== "text/html" || !this[$content]) {
      
      return HTMLResult.EMPTY;
    }
    return this[$content][$toHTML](availableSpace);
  }
}
class ExObject extends XFAObject {