stackPolicyUrl

Location of a file containing the updated stack policy. The URL must point to a policy (max size: 16KB) located in an S3 bucket in the same Region as the stack. You can specify either the StackPolicyBody or the StackPolicyURL parameter, but not both.

You might update the stack policy, for example, in order to protect a new resource that you created during a stack update. If you don't specify a stack policy, the current policy that is associated with the stack is unchanged.