- Revised `OpenAPI v2` fetching for CustomResourceDefinitions. CRDs are now aggregated lazily,
  which improves resource usage during installation of many CRDs. As a result, the first request
  to fetch the OpenAPI may be slower. ([#118808](https://github.com/kubernetes/kubernetes/pull/118808), [@Jefftree](https://github.com/Jefftree))

and now perform a more rigorous reconciliation to ensure static pods (especially those that use fixed UIDs) are restarted.  As a side effect of these changes static pods will be restarted with lower latency than before (2s vs 4s, on average) and rapid updates to pod configuration should take effect sooner.
  
  A new metric `kubelet_known_pods` has been added at ALPHA stability to report the number of pods a Kubelet is tracking in a number of internal states.  Operators may use the metrics...

For more information, see [#51899](https://github.com/kubernetes/kubernetes/issues/51899).

- Allowed attached volumes to be mounted quicker by skipping exponential backoff when checking for reported-in-use volumes. ([#106853](https://github.com/kubernetes/kubernetes/pull/106853), [@gnufied](https://github.com/gnufied))
- Alowed useful inclusion of `-args $prog_args` in KUBE_TEST_ARGS, when doing `make test-integration`. ([#107516](https://github.com/kubernetes/kubernetes/pull/107516), [@MikeSpreitzer](https://github.com/MikeSpreitzer))

- When scheduling a mix of pods using `ResourceClaims` and others that don't, scheduling a pod with `ResourceClaims` has a lower impact on scheduling latency. ([#121876](https://github.com/kubernetes/kubernetes/pull/121876), [@pohly](https://github.com/pohly))

### Other (Cleanup or Flake)

- Allow using lower and upper case feature flag value, the name has to match still ([#121441](https://github.com/kubernetes/kubernetes/pull/121441), [@soltysh](https://github.com/soltysh)) [SIG CLI]

  This change added the following metrics:
    - `apiserver_flowcontrol_nominal_limit_seats`: Nominal number of execution seats configured for each priority level
    - `apiserver_flowcontrol_lower_limit_seats`: Configured lower bound on number of execution seats available to each priority level
    - `apiserver_flowcontrol_upper_limit_seats`: Configured upper bound on number of execution seats available to each priority level