* Created a new `dryRun` query parameter for mutating endpoints. If the parameter is set, then the query will be rejected, as the feature is not implemented yet. This will allow forward compatibility with future clients; otherwise, future clients talking with older apiservers might end up modifying a resource even if they include the `dryRun` query parameter. ([#63557](https://github.com/kubernetes/kubernetes/pull/63557), [@ap...

- Locked the (generally available) feature gate `ExecProbeTimeout` to true. ([#134635](https://github.com/kubernetes/kubernetes/pull/134635), [@vivzbansal](https://github.com/vivzbansal)) [SIG Node and Testing]
- Metrics: Excluded `dryRun` requests from `apiserver_request_sli_duration_seconds`. ([#131092](https://github.com/kubernetes/kubernetes/pull/131092), [@aldudko](https://github.com/aldudko)) [SIG API Machinery and Instrumentation]

- Fixed client cert setup in delegating authentication logic ([#69430](https://github.com/kubernetes/kubernetes/pull/69430), [@DirectXMan12](https://github.com/DirectXMan12))
- OpenAPI spec and API reference now reflect dryRun query parameter for POST/PUT/PATCH operations ([#69359](https://github.com/kubernetes/kubernetes/pull/69359), [@roycaihw](https://github.com/roycaihw))

- Fix kubectl create --dryrun client ignores namespace ([#90502](https://github.com/kubernetes/kubernetes/pull/90502), [@zhouya0](https://github.com/zhouya0))