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.
constructor(attributes) {
    super(TEMPLATE_NS_ID, "overflow");
    this.id = attributes.id || "";
    this.leader = attributes.leader || "";
    this.target = attributes.target || "";
    this.trailer = attributes.trailer || "";
    this.use = attributes.use || "";
    this.usehref = attributes.usehref || "";
  }
  [$getExtra]() {
    if (!this[$extra]) {
      const parent = this[$getParent]();
      const root = this[$getTemplateRoot]();
      const target = root[$searchNode](this.target, parent);
      const leader = root[$searchNode](this.leader, parent);
      const trailer = root[$searchNode](this.trailer, parent);
      this[$extra] = {
        target: (target && target[0]) || null,
        leader: (leader && leader[0]) || null,
        trailer: (trailer && trailer[0]) || null,
        addLeader: false,
        addTrailer: false,
      };
    }
    return this[$extra];
  }
}
class PageArea extends XFAObject {