The following code is flagged as dead (since it's *replacing* rather than updating the existing Object):
https://github.com/mozilla/pdf.js/blob/4483cba72410027acf46630ebf252ae529704476/src/core/xfa/template.js#L2336-L2339
according to the alert in https://github.com/mozilla/pdf.js/security/code-scanning/103?query=ref%3Arefs%2Fheads%2Fmaster

Looking at the surrounding code, I can see a couple of possibilities here:
 1. This is indeed just dead code, which should be removed.
 2. The code should be moved up, and placed just *above* the previous block instead.
 3. There should be other, more invasive, changes made to this code...

/cc @calixteman Which solution is correct here?
Assuming it's either option 1 or 2, I can submit a patch to fix this.
super(TEMPLATE_NS_ID, "subform",  true);
    this.access = getStringOption(attributes.access, [
      "open",
      "nonInteractive",
      "protected",
      "readOnly",
    ]);
    this.allowMacro = getInteger({
      data: attributes.allowMacro,
      defaultValue: 0,
      validate: x => x === 1,
    });
    this.anchorType = getStringOption(attributes.anchorType, [
      "topLeft",
      "bottomCenter",
      "bottomLeft",
      "bottomRight",
      "middleCenter",
      "middleLeft",
      "middleRight",
      "topCenter",
      "topRight",
    ]);
    this.colSpan = getInteger({
      data: attributes.colSpan,
      defaultValue: 1,
      validate: n => n >= 1 || n === -1,
    });
    this.columnWidths = (attributes.columnWidths || "")
      .trim()