Ok, I work in the appliance business, repairing, installing, and sales of appliances.
I can almost guarantee that is the front panel to a dishwasher. A lot of dishwasher models have
interchangeable front panels. Some have 2 panels that you can slide in and out to change the
front panel color to match your other kitchen appliances. I have a GE Potscrubber Dishwasher
in my shop now, that has 2 panels roughly 2ft wide, and about 26" tall. One is white on one side,
black on the other, and also has an almond panel aswell.
That's exactly what that looks like. Now, where it came from, is beyond me. I am almost certain that
the metal piece belongs to a dishwasher.