yes Fred , it is the cord winder. There is an indentation that is the carrying handle. There is also a button that is pushed to retract the cord. This whole box on the handle was featured on the Eureka Precision upright. Behind the box but right in front of the handle is a slot where you can store an extra F&G bag!
The switch is on the front there too, across from the cord reel button.
I didn't know there was a Sanitaire version of this, but would venture a guess this is among the last cord reel models produced by Eureka.