- Added RBAC reconcile commands with `kubectl auth reconcile -f FILE`. When
  passed a file which contains RBAC roles, rolebindings, clusterroles, or
  clusterrolebindings, this command computes covers and adds the missing rules.
  The logic required to properly apply RBAC permissions is more complicated

- Kube-apiserver: The `rbac.authorization.k8s.io/v1alpha1` API version is removed; use the `rbac.authorization.k8s.io/v1` API, available since v1.8. The `scheduling.k8s.io/v1alpha1` API version is removed; use the `scheduling.k8s.io/v1` API, available since v1.14. ([#104248](https://github.com/kubernetes/kube...

Beta and enabled the feature by default. This implies that 1) for new clusters kubeadm will start using the `kube-system/kubelet-config` naming scheme for the kubelet ConfigMap and RBAC rules, instead of the legacy `kubelet-config-x.yy` naming. 2) during upgrade, kubeadm will only write the new scheme ConfigMap and RBAC objects. To disable the feature you can pass `UnversionedKubeletConfigMap: false` in the kubeadm config for new clusters. For upgrade on existing clusters you can also override the...

- Kubeadm: avoided uploading a defaulted flag value "--authorization-mode=Node,RBAC" for the kube-apiserver in the ClusterConfiguration stored in the "kube-system/kubeadm-config" ConfigMap. "Node,RBAC" are already the kubeadm defaults for this flag, so this action is redundant. ([#123555](https://github.com/kubernetes/kubernetes/pull/123555), [@neolit123](https://github.com/neolit123))

- Kubeadm: graduated the kubeadm specific feature gate `UnversionedKubeletConfigMap` to GA and locked it to `true` by default. The kubelet related ConfigMap and RBAC rules are now locked to have a simplified naming `*kubelet-config` instead of the legacy naming `*kubelet-config-x.yy`, where `x.yy` was the version of the control plane. If you have previously used the old naming format with `UnversionedKubeletConfigMap=false`,...

- Added privileges for `EndpointSlice` to the default view & edit RBAC roles. ([#101203](https://github.com/kubernetes/kubernetes/pull/101203), [@mtougeron](https://github.com/mtougeron))

 - `kubeadm`: a separate "super-admin.conf" file is now deployed. The User in `admin.conf` is now bound to a new RBAC Group `kubeadm:cluster-admins` that has `cluster-admin` `ClusterRole` access. The User in `super-admin.conf` is now bound to the `system:masters` built-in super-powers / break-glass Group that can bypass RBAC. Before this change, the default `admin.conf` was bound to `system:masters` Group, which was undesired. Executing `kubeadm init phase kubeconfig...