- Exposes and sets a default timeout for the SubjectAccessReview client for DelegatingAuthorizationOptions ([#96152](https://github.com/kubernetes/kubernetes/pull/96152), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery and Cloud Provider]

* Change `kubeadm create token` to default to the group that almost everyone will want to use.  The group is system:bootstrappers:kubeadm:default-node-token and is the group that kubeadm sets up, via an RBAC binding, for auto-approval (system:certificates.k8s.io:certificatesigningrequests:nodeclient). ([#53512](https://github.com/kubernetes/kubernetes/pull/53512), [@jbeda](https://github.com/jbeda))

## Changelog since v1.15.3

### Other notable changes

* Restores compatibility with kubectl client-side validation when structural schemas are present in a CRD which sets spec.preserveUnknownFields=true ([#82666](https://github.com/kubernetes/kubernetes/pull/82666), [@liggitt](https://github.com/liggitt))

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]

- Updated the Partitionable Devices feature to support referencing counter sets across ResourceSlices within the same resource pool. Devices from incomplete pools were no longer considered for allocation. This change introduced backwards-incompatible updates to the alpha feature, requiring any ResourceSlices using it to be removed...

      newEntry.setValueReference(valueReference.copyFor(this.valueReferenceQueue, value, newEntry));
      return newEntry;
    }

    /** Sets a new value of an entry. Adds newly created entries at the end of the access queue. */
    @GuardedBy("this")
    void setValue(ReferenceEntry<K, V> entry, K key, V value, long now) {

          <type>String</type>
          <required>true</required>
          <description>The unique id for this report set, to be used during POM inheritance and profile injection
            for merging of report sets.
          </description>
          <defaultValue>default</defaultValue>
        </field>
        <field>
          <name>reports</name>
          <version>4.0.0+</version>

      newEntry.setValueReference(valueReference.copyFor(this.valueReferenceQueue, value, newEntry));
      return newEntry;
    }

    /** Sets a new value of an entry. Adds newly created entries at the end of the access queue. */
    @GuardedBy("this")
    void setValue(ReferenceEntry<K, V> entry, K key, V value, long now) {

- Changed how the API server handles updates to `.spec.defaultBackend` of Ingress objects.

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]