pilot/pkg/xds/testdata/ecds.yaml

apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  name: test
spec:
  configPatches:
  - applyTo: EXTENSION_CONFIG
    match:
      context: SIDECAR_INBOUND
    patch:
      operation: ADD
      value:
        name: extension-config
        typed_config:
          "@type": type.googleapis.com/udpa.type.v1.TypedStruct
          type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
          value:
            config:
              vm_config:
                code:
                  remote:
                    http_uri:
                      uri: https://test-url