Clarify that we aim at a real defaulter

keps/sig-api-machinery/20190426-crd-defaulting.md

@@ -77,7 +77,8 @@ This KEP proposes to apply these default values during deserialization, in the s
 
 ### Non-Goals
 
-* allow non-constant defaults. Native Golang code can of course set defaults which depends on other fields of a JSON object. This is out of scope here and would need some kind of defaulting webhook.
+* allow non-constant defaults: native Golang code can of course set defaults which depends on other fields of a JSON object. This is out of scope here and would need some kind of defaulting webhook.
+* native-type declarative defaulting: this KEP is about CRDs. Though it might be desireable to support the same `// +default=<some-json-value>` tag and a mechanism in `k8s.io/apiserver` to evaluate defaults in native, generic registries, this is out-of-scope of the KEP though.
 
 ## Proposal
 
@@ -90,7 +91,7 @@ We propose to
   * undefined (`_, ok := obj[field]; !ok`)
   * `nil` if the field not nullable.
 
-We do this in the serializer just after the binary payload has been unmarshalled into an `map[string]interface{}`, pruning of [KEP: Pruning for CustomResources](https://github.com/kubernetes/enhancements/pull/709) was done, compare the yellow boxes in the following figure:
+We do this in the serializer by passing a real defaulter to [`versioningserializer.NewCodec`](https://github.com/kubernetes/apimachinery/blob/master/pkg/runtime/serializer/versioning/versioning.go#L49) such that defaulting is done natively just after the binary payload has been unmarshalled into an `map[string]interface{}` and pruning of [KEP: Pruning for CustomResources](https://github.com/kubernetes/enhancements/pull/709) was done, compare the yellow boxes in the following figure:
 
 ![Decoding steps which must apply defaults](20190426-crd-defaulting-pipeline.png)