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.
delete this.caption[$extra];
    }
    this[$pushPara]();
    const caption = this.caption
      ? this.caption[$toHTML](availableSpace).html
      : null;
    const savedW = this.w;
    const savedH = this.h;
    let marginH = 0;
    let marginV = 0;
    if (this.margin) {
      marginH = this.margin.leftInset + this.margin.rightInset;
      marginV = this.margin.topInset + this.margin.bottomInset;
    }
    let borderDims = null;
    if (this.w === "" || this.h === "") {
      let width = null;
      let height = null;
      let uiW = 0;
      let uiH = 0;
      if (this.ui.checkButton) {
        uiW = uiH = this.ui.checkButton.size;
      } else {
        const { w, h } = layoutNode(this, availableSpace);
        if (w !== null) {
          uiW = w;
          uiH = h;
        } else {
          uiH = getMetrics(this.font,  true).lineNoGap;
        }