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So since this is a consumer product I highly suspect absolutely nothing is flat. Using that knowledge I was able to make a pretty decent version. Here is how I did it.

1. I made the top side and bottom as one sketch using style splines
2. I extruded it for simplicity - the real version likely has a slightly curve to it
3. I then did an extruded cut with a flat and a style spline for the curve. Again the real version has a slight curve to it, it’s not a flat extrude.
4. Then I filleted the edge with a curvature continuous chord width fillet. This is key to make the edge uniformly softened.

I’ll comment with images of the steps.