This is to keep the engine from falling out when removing the subframe. The brackets that actually attach to the engine are special tools specifically for this engine family (m176, m177, m178). In this case, the engine was the only major component still in the vehicle, but you’ve seen pictures of that already in my last post.
Still not done in case you’re curious. Maybe at 75% now. Haven’t had a ton of time to work on it.