We still use lacing cord for most of our aircraft harnesses. Nobody but the engineers and technicians ever get to see it, which is a shame because it really does look beautiful.
The black ties is the lacing cord. Sometimes its just small pieces that bundle the wire every few inches, sometimes its a long continuous piece that is looped at those intervals. The black nylon overbraid is for any wiring harness that is exposed or handled routinely. They typically don't use it on anything that gets tucked away. Also notice the heavy harness supports on those connectors. This is thick gauge cable and a lot of it. Large aerospace companies have shops and techs dedicated to making these all day long.
