- Remove `kubernetes.io/grpc` standard appProtocol ([#116866](https://github.com/kubernetes/kubernetes/pull/116866), [@LiorLieberman](https://github.com/LiorLieberman)) [SIG API Machinery and Apps]

### Other notable changes

* Allow for configuring etcd hostname in the manifest ([#54403](https://github.com/kubernetes/kubernetes/pull/54403), [@wojtek-t](https://github.com/wojtek-t))
* Allow standard flags in client-gen. ([#53999](https://github.com/kubernetes/kubernetes/pull/53999), [@sttts](https://github.com/sttts))

- External credential provider plugins will now have their standard error output logged by kubelet upon failures. ([#117448](https://github.com/kubernetes/kubernetes/pull/117448), [@cartermckinnon](https://github.com/cartermckinnon))

  CVE-2021-29923 golang standard library "net" - Improper Input Validation of octal literals in golang 1.16.2 and below standard library "net" results in indeterminate SSRF & RFI vulnerabilities.

- Exec plugin authors can override default handling of standard input via new `interactiveMode` kubeconfig field. ([#99310](https://github.com/kubernetes/kubernetes/pull/99310), [@ankeesler](https://github.com/ankeesler))

- Text logging in Kubernetes components now uses [textlogger](https://pkg.go.dev...

- Added `UserNamespacesPodSecurityStandards` feature gate to enable user namespace support for Pod Security Standards.
  Enabling this feature will modify all Pod Security Standard rules to allow setting: `spec[.*].securityContext.[runAsNonRoot,runAsUser]`.
  This feature gate should only be enabled if all nodes in the cluster support the user namespace feature and have it enabled.

    - `apiserver_flowcontrol_demand_seats_average`: Time-weighted average, over last adjustment period, of demand_seats
    - `apiserver_flowcontrol_demand_seats_stdev`: Time-weighted standard deviation, over last adjustment period, of demand_seats
    - `apiserver_flowcontrol_demand_seats_smoothed`: Smoothed seat demands
    - `apiserver_flowcontrol_target_seats`: Seat allocation targets