* CustomResourceDefinitions: OpenAPI v3 validation schemas containing `$ref`references are no longer permitted (valid references could not be constructed previously because property ids were not permitted either). Before upgrading, ensure CRD definitions do not include those `$ref` fields. ([#58438](https://github.com/kubernetes/kubernetes/pull/58438), [@carlory](https://github.com/carlory))

### Other notable changes

* CustomResourceDefinitions: OpenAPI v3 validation schemas containing `$ref`references are no longer permitted (valid references could not be constructed previously because property ids were not permitted either). Before upgrading, ensure CRD definitions do not include those `$ref` fields. ([#58438](https://github.com/kubernetes/kubernetes/pull/58438), [@carlory](https://github.com/carlory))

### Feature

   * serializable.
   *
   * <p>This method's signature will not permit you to convert a {@code NavigableMap<? extends K,
   * V>} to a {@code NavigableMap<K, V>}. If it permitted this, the returned map's {@code
   * comparator()} method might return a {@code Comparator<? extends K>}, which works only on a
   * particular subtype of {@code K}, but promise that it's a {@code Comparator<? super K>}, which

   * serializable.
   *
   * <p>This method's signature will not permit you to convert a {@code NavigableMap<? extends K,
   * V>} to a {@code NavigableMap<K, V>}. If it permitted this, the returned map's {@code
   * comparator()} method might return a {@code Comparator<? extends K>}, which works only on a
   * particular subtype of {@code K}, but promise that it's a {@code Comparator<? super K>}, which

    The Panther took pie-crust, and gravy, and meat,
    While the Owl had the dish as its share of the treat.
    When the pie was all finished, the Owl, as a boon,
    Was kindly permitted to pocket the spoon:
    While the Panther received knife and fork with a growl,
    And concluded the banquet--]

  `What IS the use of repeating all that stuff,' the Mock Turtle

    * Uso de modelos jerárquicos de Pydantic, `List` y `Dict` de `typing` de Python, etc.
    * Y los validadores permiten definir, verificar y documentar de manera clara y fácil esquemas de datos complejos como JSON Schema.
    * Puedes tener objetos JSON profundamente **anidados** y validarlos todos y anotarlos.
* **Extensible**:

- Kube-apiserver: events created via the `events.k8s.io` API group for cluster-scoped objects are now permitted in the default namespace as well for compatibility with events clients and the `v1` API ([#100125](https://github.com/kubernetes/kubernetes/pull/100125), [@h4ghhh](https://github.com/h4ghhh))

          @Override
          boolean isPermitted(Exception exception) {
            return exception instanceof UnsupportedOperationException
                || exception instanceof IllegalStateException;
          }
        };
    static final PermittedMetaException UOE =
        new PermittedMetaException("UnsupportedOperationException") {
          @Override
          boolean isPermitted(Exception exception) {

          @Override
          boolean isPermitted(Exception exception) {
            return exception instanceof UnsupportedOperationException
                || exception instanceof IllegalStateException;
          }
        };
    static final PermittedMetaException UOE =
        new PermittedMetaException("UnsupportedOperationException") {
          @Override
          boolean isPermitted(Exception exception) {