Originally Posted By: tanstaafl.
...
I didn't think that a five-volt 0.85A output could make that much heat.

What do you suppose happened here?
...
My guess is that the charger itself failed internally and generated much more heat than the wattage output specification.

Consider yourself fortunate that the damage was limited to the cable and the charger. I would not trust the charger ever again and would consign both cable and charger to the trash immediately.

Up to you whether you want to pursue a warranty claim with Amazon or search online for a failure trend among other Kindle owners.