- Changed NodeToStatusMap from a map to a struct and exposed methods to access the entries. Added absentNodesStatus, which informs the status of nodes that are absent in the map. For developers of out-of-tree PostFilter plugins, ensure to update the usage of NodeToStatusMap. Additionally, NodeToStatusMap should eventually be renamed to NodeToStatusReader. ([#126022](https://github.com/kubernetes/kubernetes/pull/126022),...

- Improved scheduling performance when many nodes, and prefilter returned 1-2 nodes (e.g. daemonset)
  
  For developers of out-of-tree PostFilter plugins, note that the semantics of NodeToStatusMap are changing: A node with an absent value in the NodeToStatusMap should be interpreted as having an UnschedulableAndUnresolvable status. ([#125197](https://github.com/kubernetes/kubernetes/pull/125197), [@gabesaba](https://github.com/gabesaba))

- Improved scheduling performance when many nodes, and prefilter returns 1-2 nodes (e.g. daemonset)
  
  For developers of out-of-tree PostFilter plugins, note that the semantics of NodeToStatusMap are changing: A node with an absent value in the NodeToStatusMap should be interpreted as having an UnschedulableAndUnresolvable status ([#125307](https://github.com/kubernetes/kubernetes/pull/125307), [@gabesaba](https://github.com/gabesaba)) [SIG Scheduling]

- Improved scheduling performance when many nodes, and prefilter returns 1-2 nodes (e.g. daemonset)
  
  For developers of out-of-tree PostFilter plugins, note that the semantics of NodeToStatusMap are changing: A node with an absent value in the NodeToStatusMap should be interpreted as having an UnschedulableAndUnresolvable status ([#125309](https://github.com/kubernetes/kubernetes/pull/125309), [@gabesaba](https://github.com/gabesaba)) [SIG Scheduling]

- Improved scheduling performance when many nodes, and prefilter returns 1-2 nodes (e.g. daemonset)
  
  For developers of out-of-tree PostFilter plugins, note that the semantics of NodeToStatusMap are changing: A node with an absent value in the NodeToStatusMap should be interpreted as having an UnschedulableAndUnresolvable status ([#125306](https://github.com/kubernetes/kubernetes/pull/125306), [@gabesaba](https://github.com/gabesaba)) [SIG Scheduling]

- Improved scheduling performance when many nodes, and prefilter returns 1-2 nodes (e.g. daemonset)
  
  For developers of out-of-tree PostFilter plugins, note that the semantics of NodeToStatusMap are changing: A node with an absent value in the NodeToStatusMap should be interpreted as having an UnschedulableAndUnresolvable status ([#125308](https://github.com/kubernetes/kubernetes/pull/125308), [@gabesaba](https://github.com/gabesaba)) [SIG Scheduling]

  - When registering with a 1.17+ API server, a CustomResourceDefinition conversion webhook can now request that only `v1` ConversionReview requests be sent to them. Previously, conversion webhooks were required to support receiving `v1beta1` ConversionReview...

- The `AdmissionReview` API sent to and received from admission webhooks has been promoted to `admission.k8s.io/v1`. Webhooks can specify a preference for receiving `v1` AdmissionReview objects with `admissionReviewVersions: ["v1","v1beta1"]`, and must respond with an API object in the same `apiVersion` they are sent. When webhooks use `admission.k8s.io/v1`, the following additional validation is performed on their responses:...

a token with the given audience bound to the current pod and its service account. This KSA token along with required annotations on the KSA defined in configuration will be sent to the credential provider plugin via its standard input (along with the image information that is already sent today). The KSA annotations to be sent are configurable in the kubelet credential provider configuration. ([#128372](https://github.com/kubernetes/kubernetes/pull/128372), [@aramase](https://github.com/aramase))...

### Extensibility around core Kubernetes APIs

#### CustomResourceDefinitions Pruning