<p>
The following terms are used to denote specific Unicode character categories:
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<pre class="ebnf">
newline        = /* the Unicode code point U+000A */ .
unicode_char   = /* an arbitrary Unicode code point except newline */ .
unicode_letter = /* a Unicode code point categorized as "Letter" */ .
unicode_digit  = /* a Unicode code point categorized as "Number, decimal digit" */ .
</pre>

<p>

    * New documentation about returning arbitrary `dict`s in responses: [Response with arbitrary `dict`](https://fastapi.tiangolo.com/tutorial/extra-models/#response-with-arbitrary-dict).
    * **Technical Details**:
        * When declaring a `response_model` it is used directly to generate the response content, from whatever was returned from the *path operation function*.

- Kubelet can now parse PEM file containing both TLS certificate and key in arbitrary order. Previously key was always required to be first. ([#69536](https://github.com/kubernetes/kubernetes/pull/69536), [@awly](https://github.com/awly))

affinity/anti-affinity allow you to specify rules for restricting which node(s) a pod can schedule onto, based on the labels on the node. Pod affinity/anti-affinity allow you to specify rules for spreading and packing pods relative to one another, across arbitrary topologies (node, zone, etc.) These affinity rules are now be specified in a new-in-1.6 `affinity` field of the PodSpec. Kubernetes 1.6 continues to support the alpha `scheduler.alpha.kubernetes.io/affinity` annotation on the Pod if you explicitly...

  // Data contains the secret data. Each key must consist of alphanumeric
  // characters, '-', '_' or '.'. The serialized form of the secret data is a
  // base64 encoded string, representing the arbitrary (possibly non-string)
  // data value here. Described in https://tools.ietf.org/html/rfc4648#section-4
  // +optional
  map<string, bytes> data = 2;

- Added GenericPVCDataSource feature gate to enable using arbitrary custom resources as the data source for a PVC. ([#88636](https://github.com/kubernetes/kubernetes/pull/88636), [@bswartz](https://github.com/bswartz)) [SIG Apps and Storage]

* the test/e2e/e2e.test binary can test arbitrary storage drivers, see the `-storage.testdriver` parameter ([#72836](https://github.com/kubernetes/kubernetes/pull/72836), [@pohly](https://github.com/pohly))

- Added a feature that allows a `StatefulSet` to start numbering replicas from an arbitrary non-negative ordinal, using the `.spec.ordinals.start` field. ([#112744](https://github.com/kubernetes/kubernetes/pull/112744), [@pwschuurman](https://github.com/pwschuurman))

    <!-- QuickTime video, and all MP4 formats, are based on it -->
    <acronym>QTFF</acronym>
    <_comment>QuickTime container format</_comment>
  </mime-type>
  <mime-type type="application/mp4">
    <!-- Arbitrary data stored in a MP4 container -->
    <_comment>MP4 container format</_comment>
    <glob pattern="*.mp4s"/>
    <sub-class-of type="application/quicktime" />
  </mime-type>

[CSI Ephemeral Volume](https://github.com/kubernetes/enhancements/tree/master/keps/sig-storage/596-csi-inline-volumes) feature allows CSI volumes to be specified directly in the pod specification for ephemeral use cases. They can be used to inject arbitrary states, such as configuration, secrets, identity, variables or similar information, directly inside pods using a mounted volume. This was initially introduced in 1.15 as an alpha feature, and it moved to GA. This feature is used by some CSI drivers...