<h3 id="Identifiers">Identifiers</h3>

<p>
Identifiers name program entities such as variables and types.
An identifier is a sequence of one or more letters and digits.
The first character in an identifier must be a letter.
</p>
<pre class="ebnf">
identifier = letter { letter | unicode_digit } .
</pre>
<pre>
a
_x9
ThisVariableIsExported
αβ
</pre>

<p>

* Change docker metrics to conform metrics guidelines and using histogram for better aggregation. ([#72323](https://github.com/kubernetes/kubernetes/pull/72323), [@danielqsj](https://github.com/danielqsj))
    * The following metrics are deprecated, and will be removed in a future release:

### Node

America/Mexico_City America/Miquelon America/Moncton America/Monterrey America/Montevideo America/Montreal America/Montserrat America/Nassau America/New_York America/Nipigon America/Nome America/Noronha America/North_Dakota/Beulah America/North_Dakota/Center America/North_Dakota/New_Salem America/Nuuk America/Ojinaga America/Panama America/Pangnirtung America/Paramaribo America/Phoenix America/Port-au-Prince America/Port_of_Spain America/Porto_Acre America/Porto_Velho America/Puerto_Rico America/Punta_Arenas...

// https://www.iana.org/domains/root/db/cbn.html
cbn

// cbre : CBRE, Inc.
// https://www.iana.org/domains/root/db/cbre.html
cbre

// center : Binky Moon, LLC
// https://www.iana.org/domains/root/db/center.html
center

// ceo : XYZ.COM LLC
// https://www.iana.org/domains/root/db/ceo.html
ceo

// cern : European Organization for Nuclear Research ("CERN")

- kubeadm: Added better handling of errors during unmount when calling `kubeadm reset`. When failing to unmount directories under `/var/run/kubelet`, kubeadm will now throw an error instead of showing a warning and continuing to clean up said directory. In such situations, it is better for you to inspect the problem and resolve it manually. Then, you can call `kubeadm reset` again to complete the cleanup....

- EndpointSlice controller now handles terminating pods correctly and is better at preventing race conditions. ([#89118](https://github.com/kubernetes/kubernetes/pull/89118), [@robscott](https://github.com/robscott)) [SIG Apps and Network]

  Users should update import path for these types from `k8s.io/kubernetes/pkg/scheduler/framework` to `k8s.io/kube-scheduler/framework` and update use of fields (to use getter/setter functions instead) where needed. ([#132457](https://github.com/kubernetes/kubernetes/pull/132457), [@ania-borowiec](https://github.com/ania-borowiec)) [SIG Node, Scheduling, Storage and Testing]

- The getters for the field name and typeDescription of the Reflector struct were renamed. ([#128035](https://github.com/kubernetes/kubernetes/pull/128035), [@alexanderstephan](https://github.com/alexanderstephan)) [SIG API Machinery]

  - Different configuration types can be supplied all in the same file separated by `---`.
- Improved CRI handling
  - crictl is no longer required in docker-only setups.
  - Better detection of installed CRI.
  - Better output for image pull errors.
- Improved air-gapped and offline support
  - kubeadm now handles air-gapped environments by using the local client version as a fallback.