Don’t feel bad. I posted the same question a while back. As did a lot of other people.
The problem is, it’s difficult to use the search function to find an answer because if you knew what to search for - then you’d know what it is. So the site ends up with a bunch of questions. All showing a picture of the same thing with a “what is this for” text.
This is one of those questions that will be asked 100 times. And still be valid each and every time it’s asked. The answer is not obvious until you actually take your top off.
Maybe it's just me, but since I had several months to wait on my Bronco, I read through the manual and then reviewed several items a few times so that I'd know how to remove stuff. It's pretty clearly shown in the 'Removable Vehicle Components' section.
The resistance to read the manual is a wonder to me. I'd want to know all I could about my new vehicle. Yeah, I skim the 'starting and stopping' sections like others as we kind of have to already know the basics, but 'Removable components' is unique to this truck.
Between this (search on "What is this" on here) and how to turn on the Fog lights, I find it funny that so many people have no idea.