Appears to be working in Firefox but at least Chrome & Safari are broken. Should be a really recent regression so very few possible changes to blame...

Easiest repo: the todo list on our homepage.

if (internalInstance) {
    var owner = internalInstance._currentElement._owner || null;
    if (owner) {
      var name = owner.getName();
      if (name) {
        return ' This DOM node was rendered by `' + name + '`.';
      }
    }
  }
  return '';
}
function friendlyStringify(obj) {