Shore power cord has a burned looking spot

Hookster57 said:
Looks like it got hot. Should I worry? What's the problem?

If the cord itself has a burned spot and you are sure it isn't a stain, you should not use the cord. It probably has a break in the internal wires and is overheating. That can lead to a fire.
It is unususual for an overloaded cord to burn in the middle, it usually overheats at the connectors or near to the ends.
 
Take a sharp knife and in one small spot slightly trim surface, is same color underneath?