good question - inspection is not easy, to say the least
You can see part of the racks through the gap below the headboard in mid-cycle, but you will not be able to see the drive motors.
You can see the rest of it from below if you empty the outside storage compartment on the slideout, get in there with a phillips screw driver and remove the panels fastened to the slideout frame above the compartment, and get in there with a light to look at the mechanism from below. (You need to be reasonably thin to do this.)
If you want to get a full view, you will need to remove the mattress, take the piano hinge screws out that secure the mattress board to the horizontal part of the mechanism, and slide the board all the way to the cabinets to expose the rest of it. I'm thin enough to climb down in the well above the storage compartment for a close look and work on it if necessary. You can observe the mechanism throughout its full range of motion if you do this to see what's going on when it makes strange noises.
If you choose to do this, an electric screw driver is handy with a fillips and a nut driver for the screws along the horizontal member. Also be careful to not over tighten the screws when you replace them - it is easy to strip the threads in the holes in the aluminum - just snug them up. There are enough of them that collectively they are strong.
(You won't find this information in your owner's manual :-)