The white lens above the buttons holds two night-light type bulbs that give off lots of light, when the machine is running. No simple on/off switch for it, which would have been nice.
Plus, as was said before, there was a cycle sequence light bar that would have a light for each phase, and would gradually de-energize each bar as the cycle progressed.
Then there is the light for sterilizing rinse and hold option, showing that the timer was not progressing while the water was heating.
I had several of these, back in the day (early 1980s). Picked up off the curb. They usually had a rust through spot in the tub, the racks heavily rusted, or the motor/pump was not working. Those were fun days.