
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


const header = file.peekBytes(4);
    return bytesToString(header) === "ttcf";
  }
  function isOpenTypeFile(file) {
    var header = file.peekBytes(4);
    return bytesToString(header) === "OTTO";
  }
  function isType1File(file) {
    var header = file.peekBytes(2);
    
    if (header[0] === 0x25 && header[1] === 0x21) {
      return true;
    }
    
    
    if (header[0] === 0x80 && header[1] === 0x01) {
      return true;
    }
    return false;
  }
  /**
   * Compared to other font formats, the header in CFF files is not constant
   * but contains version numbers. To reduce the possibility of misclassifying
   * font files as CFF, it's recommended to check for other font formats first.
   */
  function isCFFFile(file) {