* Allow Secret & ConfigMap keys to contain caps, dots, and underscores ([#25458](https://github.com/kubernetes/kubernetes/pull/25458), [@errm](https://github.com/errm))

 *
 * @author Charles Fry
 * @author Bob Lee ({@code com.google.common.collect.MapMaker})
 * @author Doug Lea ({@code ConcurrentHashMap})
 */
@SuppressWarnings({
  "GoodTime", // lots of violations (nanosecond math)
  "nullness", // too much trouble for the payoff
})
@GwtCompatible
@NullUnmarked // TODO(cpovirk): Annotate for nullness.

  * Fix a bug where Kubelet does not ignore pod manifest files starting with dots ([#45111](https://github.com/kubernetes/kubernetes/pull/45111), [@dwradcliffe](https://github.com/dwradcliffe))

    public static final String LABELS_PN = "{labels.pn}";

    /** The key of the message: Scheme */
    public static final String LABELS_PROTOCOL_SCHEME = "{labels.protocolScheme}";

    /** The key of the message: Purge Bots */
    public static final String LABELS_PURGE_BY_BOTS = "{labels.purgeByBots}";

    /** The key of the message: Log Level */
    public static final String LABELS_LOG_LEVEL = "{labels.logLevel}";

enabled.([#51436](https://github.com/kubernetes/kubernetes/pull/51436))

* [Action required] The validation rule for metadata.initializers.pending[x].name is tightened. The initializer name must contain at least three segments, separated by dots. You can create objects with pending initializers and not rely on the API server to add pending initializers according to `initializerConfiguration`. If you do so, update the initializer name in the existing objects and the configuration files to comply...

 *
 * @author Charles Fry
 * @author Bob Lee ({@code com.google.common.collect.MapMaker})
 * @author Doug Lea ({@code ConcurrentHashMap})
 */
@SuppressWarnings({
  "GoodTime", // lots of violations (nanosecond math)
  "nullness", // too much trouble for the payoff
})
@GwtCompatible
@NullUnmarked // TODO(cpovirk): Annotate for nullness.

### Node Components
* Kubelet config should ignore file start with dots.
  ([#39196](https://github.com/kubernetes/kubernetes/pull/39196), [@resouer](https://github.com/resouer))
* Bump GCI to gci-stable-56-9000-84-2.
  ([#41819](https://github.com/kubernetes/kubernetes/pull/41819),

- kube-proxy: os exit when CleanupAndExit is set to true ([#76732](https://github.com/kubernetes/kubernetes/pull/76732), [@JieJhih](https://github.com/JieJhih))
- Kubernetes will now allow trailing dots in the externalName of Services of type ExternalName. ([#78385](https://github.com/kubernetes/kubernetes/pull/78385), [@thz](https://github.com/thz))

### Node

- `StatefulSet` names must be DNS labels, rather than subdomains. Any `StatefulSet`
  which took advantage of subdomain validation (by having dots in the name) can't
  possibly have worked, because we eventually set `pod.spec.hostname` from the `StatefulSetName`,

* Action required: validation rule on metadata.initializers.pending[x].name is tightened. The initializer name needs to contain at least three segments separated by dots. If you create objects with pending initializers, (i.e., not relying on apiserver adding pending initializers according to initializerconfiguration), you need to update the initializer name in existing objects and in configuration files to comply to...