Add a few annotations added by the kubelet

This PR adds some descriptions for the annotations added by the kubelet
to Pods.

content/en/docs/reference/labels-annotations-taints/_index.md

@@ -434,6 +434,59 @@ The annotation `kubernetes.io/limit-ranger` records that resource defaults were
 and they were applied successfully.
 For more details, read about [LimitRanges](/docs/concepts/policy/limit-range).
 
+### kubernetes.io/config.hash
+
+Type: Annotation
+
+Example: `kubernetes.io/config.hash: "df7cc47f8477b6b1226d7d23a904867b"`
+
+Used on: Pod
+
+When the kubelet creates a static Pod based on a given manifest, it attaches this annotation
+to the static Pod. The value of the annotation is the UID of the Pod.
+Note that the kubelet also sets the `.spec.nodeName` to the current node name as if the Pod
+was scheduled to the node.
+
+### kubernetes.io/config.mirror
+
+Type: Annotation
+
+Example: `kubernetes.io/config.mirror: "df7cc47f8477b6b1226d7d23a904867b"`
+
+Used on: Pod
+
+For a static Pod created by the kubelet on a node, a {{< glossary_tooltip text="mirror Pod" term_id="mirror-pod" >}}
+is created on the API server. The kubelet adds an annotation to indicate that this Pod is
+actually a mirror Pod. The annotation value is copied from the [`kubernetes.io/config.hash`](#kubernetes-io-config-hash)
+annotation, which is the UID of the Pod.
+
+When updating a Pod with this annotation set, the annotation cannot be changed or removed.
+If a Pod doesn't have this annotation, it cannot be added during a Pod update.
+
+### kubernetes.io/config.source
+
+Type: Annotation
+
+Example: `kubernetes.io/config.source: "file"`
+
+Used on: Pod
+
+This annotation is added by the kubelet to indicate where the Pod comes from.
+For static Pods, the annotation value could be one of `file` or `http` depending
+on where the Pod manifest is located. For a Pod created on the API server and then
+scheduled to the current node, the annotation value is `api`.
+
+### kubernetes.io/config.seen
+
+Type: Annotation
+
+Example: `kubernetes.io/config.seen: "2023-10-27T04:04:56.011314488Z"`
+
+Used on: Pod
+
+When the kubelet sees a Pod for the first time, it may add this annotation to
+the Pod with a value of current timestamp in the RFC3339 format.
+
 ### addonmanager.kubernetes.io/mode
 
 Type: Label