- Adds feature gate `NodeLogQuery` which provides cluster administrators with a streaming view of logs using kubectl without them having to implement a client side reader or logging into the node. ([#96120](https://github.com/kubernetes/kubernetes/pull/96120), [@LorbusChris](https://github.com/LorbusChris))

* Websocket requests may now authenticate to the API server by passing a bearer token in a websocket subprotocol of the form `base64url.bearer.authorization.k8s.io.<base64url-encoded-bearer-token>`. ([#47740](https://github.com/kubernetes/kubernetes/pull/47740), [@liggitt](https://github.com/liggitt))

- The deprecated flag `--lock-object-namespace` and `--lock-object-name` have been removed from kube-scheduler. Please use `--leader-elect-resource-namespace` and `--leader-elect-resource-name` or ComponentConfig instead to configure those parameters. ([#119130](https://github.com/kubernetes/kubernetes/pull/119130), [@SataQiu](https://github.com/SataQiu)) [SIG Scheduling]

- Alpha implementation of Kubectl Command Headers: SIG CLI KEP 859 enabled when KUBECTL_COMMAND_HEADERS environment variable set on the client command line.
  - To enable: export KUBECTL_COMMAND_HEADERS=1; kubectl ... ([#98952](https://github.com/kubernetes/kubernetes/pull/98952), [@seans3](https://github.com/seans3)) [SIG API Machinery and CLI]

- Client-go: Optimized leaders renewing leases by updating leader lock optimistically without getting the record from the API server first. Also, a new metric `leader_election_slowpath_total` was added to allow users to monitor how many leader elections are updated non-optimistically.

- Added a path `/header?key=` to `agnhost netexec` allowing one to view what the header value is of the incoming request.

  Ex:
  ```
  $ curl -H "X-Forwarded-For: something" 172.17.0.2:8080/header?key=X-Forwarded-For
  something
  ```

- Leader Migration for controller managers graduated to beta. ([#103533](https://github.com/kubernetes/kubernetes/pull/103533), [@jiahuif](https://github.com/jiahuif)) [SIG API Machinery and Cloud Provider]

- The `--leader-elect*` CLI args are now honored in scheduler. ([#105915](https://github.com/kubernetes/kubernetes/pull/105915), [@Huang-Wei](https://github.com/Huang-Wei))

### Bug or Regression

- Client-go: fixes potential data races retrying requests using a custom io.Reader body; with this fix, only requests with no body or with string / []byte / runtime.Object bodies can be retried ([#113933](https://github.com/kubernetes/kubernetes/pull/113933), [@liggitt](https://github.com/liggitt)) [SIG API Machinery]

- 'Container `preStop` and `postStart` lifecycle handlers using `httpGet` now
  honor the specified `scheme` and `headers` fields. This enables setting custom
  headers and changing the scheme to `HTTPS`, consistent with container
  startup/readiness/liveness probe capabilities. Lifecycle handlers configured