- The NamespaceExists and NamespaceAutoProvision admission controllers have been removed, use the NamespaceLifecycle admission controller instead (#31250, @derekwaynecarr)

* Enable the PodSecurityPolicy API (which is not enabled by default):
  * `--runtime-config=extensions/v1beta1/podsecuritypolicy=true`
* Enable the PodSecurityPolicy admission plugin (which is not enabled by default):
  * `--admission-control=...,PodSecurityPolicy,...`
* Use authorization to limit users' ability to use specific PodSecurityPolicy objects

**What is the impact?**

  - A `component-helpers` library for feature registration and inference.
  - A `NodeDeclaredFeatures` scheduler plugin to match pods with nodes that provide required features.
  - A `NodeDeclaredFeatureValidator` admission plugin to validate pod updates against a node's declared features. ([#133389](https://github.com/kubernetes/kubernetes/pull/133389), [@pravk03](https://github.com/pravk03)) [SIG API Machinery, Apps, Node, Release, Scheduling and Testing]