Add new config for oauth2 scope

Author: kbatuigas

modules/reference/pages/properties/cluster-properties.adoc

@@ -2125,6 +2125,27 @@ The OAuth URI used to retrieve access tokens for Iceberg REST catalog authentica
 
 // end::iceberg_rest_catalog_oauth2_server_uri[]
 
+// tag::iceberg_rest_catalog_oauth2_scope[]
+=== iceberg_rest_catalog_oauth2_scope
+
+The OAuth scope used to retrieve access tokens for Iceberg catalog authentication. Only meaningful when `iceberg_rest_catalog_authentication_mode` is set to `oauth2`.
+
+*Requires restart:* Yes
+
+*Visibility:* `user`
+
+*Type:* string
+
+*Default:* `principal_role:all`
+
+**Related topics**:
+
+- xref:manage:iceberg/use-iceberg-catalogs.adoc[]
+
+---
+
+// end::iceberg_rest_catalog_oauth2_scope[]
+
 // tag::iceberg_rest_catalog_prefix[]
 === iceberg_rest_catalog_prefix