If it is indeed a slide lock bar, it is probably for locking your slide closed. If the Schwintek slide malfunctions, a temporary fix is to disconnect the motors so that you can push the slide in. But with the motors disconnected, you have to ensure the slide does not move back out.
This is typically done with a 2x4 or other such item wedged between the coach wall and the backside of the slide's inner wall. I have never heard of Thor supplying a slide lock bar.
Perhaps it is the awning bar - which you would have if you have a manual awning. The awning bar is a long metal pole, used to grab the strap at the top of the awning to pull it down.
If your awning is automatic (electrically extend and retract), then you would not need an awning bar.
Otherwise, I have no idea.
The only thing that works on a RV is the owner...