Microwave installation. I can't see how to remove an old Kenmore microwave. Model 564.8568511. It

Question

I can't see how to remove an old Kenmore microwave. Model 564.8568511. It isn't bolted through the cabinet above like modern installations. It almost looks like the metal shell must have been screwed to the surrounding cabinet and then the rest of the oven slid into it. Does that make sense? If so how do I release the oven and slide it back out? Thanks, Don