kyverno/test/policy/mutate/policy_mutate_endpoint.yaml

apiVersion : kyverno.io/v1
kind : ClusterPolicy
metadata :
  name : policy-endpoints
spec :
  rules:
    - name: pEP
      match:
        resources:
          kinds : 
          - Endpoints
          selector:
            matchLabels:
              label : test
      mutate:
        patchesJson6902: |-
          [
            {
              "path":"/subsets/0/ports/0/port",
              "op":"replace",
              "value":9663
            },
            {
              "path":"/metadata/labels/isMutated",
              "op":"add",
              "value":"true"
            }
          ]