in content/resources/js/prettify.js [985:1005]
function breakLeftOf(limit, copy) {
// Clone shallowly if this node needs to be on both sides of the break.
var rightSide = copy ? limit.cloneNode(false) : limit;
var parent = limit.parentNode;
if (parent) {
// We clone the parent chain.
// This helps us resurrect important styling elements that cross lines.
// E.g. in <i>Foo<br>Bar</i>
// should be rewritten to <li><i>Foo</i></li><li><i>Bar</i></li>.
var parentClone = breakLeftOf(parent, 1);
// Move the clone and everything to the right of the original
// onto the cloned parent.
var next = limit.nextSibling;
parentClone.appendChild(rightSide);
for (var sibling = next; sibling; sibling = next) {
next = sibling.nextSibling;
parentClone.appendChild(sibling);
}
}
return rightSide;
}