in src/util/xml-helpers.js [295:320]
function mergeChild (srcChild) {
const srcTag = String(srcChild.tag);
const query = srcTag + '';
let destChild;
let shouldMerge = true;
if (DENIED_TAGS.includes(srcTag)) return;
if (SINGLETONS.includes(srcTag)) {
destChild = dest.find(query);
} else {
// Check for an exact match and if you find one don't add
destChild = dest.findall(query).find(el =>
textMatch(srcChild, el) && attribMatch(srcChild, el)
);
if (destChild) shouldMerge = false;
}
if (destChild) {
dest.remove(destChild);
} else {
destChild = et.Element(srcTag);
}
mergeXml(srcChild, destChild, platform, clobber && shouldMerge);
dest.append(destChild);
}