docs: document default snapshot repository in Kibana (#6683)

deploy-manage/tools/snapshot-and-restore/_snippets/default-snapshot-repository.md

@@ -0,0 +1,21 @@
+One registered repository can be marked as the **default** snapshot repository. The default repository stores all snapshots generated by data stream lifecycle management.
+
+The first repository you register is set as the default automatically. You can change the default at any time.
+
+To set or change the default from the repositories list:
+
+1. On the **Repositories** list, open the actions menu for the repository you want to use as the default.
+2. Select **Set as default**.
+3. In the **Change default repository?** dialog, select **Change default** to confirm.
+
+You can also set or change the default from the **Register repository** and edit repository forms by turning on the **Set as default repository** switch. If a different repository is already the default, a confirmation dialog appears before the change is applied.
+
+The default repository is marked with a **Default** badge in the repositories list and the repository details flyout.
+
+The following constraints apply:
+
+- The default repository cannot be removed. To remove it, first set another repository as the default.
+- Read-only repositories cannot be set as the default.
+- URL repositories cannot be set as the default.
+
+The default repository is stored in the `repositories.default_repository` cluster setting. To set or change the default repository from {{kib}}, you need the `cluster:admin/settings/update` [cluster privilege](elasticsearch://reference/elasticsearch/security-privileges.md#privileges-list-cluster). Without it, the **Default** badge is still visible, but the set-as-default controls are hidden.

deploy-manage/tools/snapshot-and-restore/_snippets/restore-snapshot-common-prerequisites.md

@@ -2,5 +2,6 @@
 
     * [Cluster privileges](elasticsearch://reference/elasticsearch/security-privileges.md#privileges-list-cluster): `monitor`, `manage_slm`, `cluster:admin/snapshot`, and `cluster:admin/repository`
     * [Index privilege](elasticsearch://reference/elasticsearch/security-privileges.md#privileges-list-indices): `monitor` privilege on all the indices
+    * {applies_to}`stack: ga 9.5` To set or change the default snapshot repository from {{kib}}, you also need the `cluster:admin/settings/update` cluster privilege.
 
 * To register a snapshot repository or restore a snapshot, the cluster’s global metadata must be writeable. Ensure there aren’t any [cluster blocks](elasticsearch://reference/elasticsearch/configuration-reference/miscellaneous-cluster-settings.md#cluster-read-only) that prevent write access. The restore operation ignores index blocks.

deploy-manage/tools/snapshot-and-restore/elastic-cloud-hosted.md

@@ -69,6 +69,15 @@ Alternatively, you can register a repository using the {{es}} [create snapshot r
 ::::{include} _snippets/ech-snapshot-repository-linking-note.md
 ::::
 
+### Set the default snapshot repository [snapshot-repo-default]
+
+```{applies_to}
+stack: ga 9.5
+```
+
+:::{include} _snippets/default-snapshot-repository.md
+:::
+
 ## Verify a repository [snapshots-repository-verification]
 
 When you register a snapshot repository, {{es}} automatically verifies that the repository is available and functional on all master and data nodes.

deploy-manage/tools/snapshot-and-restore/self-managed.md

@@ -49,6 +49,15 @@ To register a snapshot repository, click **Register repository**.
 
 You can also register a repository using the [Create snapshot repository API]({{es-apis}}operation/operation-snapshot-create-repository).
 
+### Set the default snapshot repository [snapshot-repo-default]
+
+```{applies_to}
+stack: ga 9.5
+```
+
+:::{include} _snippets/default-snapshot-repository.md
+:::
+
 ## Self-managed repository types [self-managed-repo-types]
 
 If you manage your own {{es}} cluster, you can use the following built-in snapshot repository types: