Update documentation

docs/configuration/experimental/index.md

@@ -8,7 +8,10 @@
     "clash_api": {
       "external_controller": "127.0.0.1:9090",
       "external_ui": "folder",
-      "secret": ""
+      "secret": "",
+      "default_mode": "rule",
+      "store_selected": false,
+      "cache_file": "cache.db"
     }
   }
 }
@@ -26,7 +29,7 @@
 
 #### external_controller
 
-RESTful web API listening address. Disabled if empty.
+RESTful web API listening address. Clash API will be disabled if empty.
 
 #### external_ui
 
@@ -38,4 +41,22 @@ serve it at `http://{{external-controller}}/ui`.
 
 Secret for the RESTful API (optional)
 Authenticate by spedifying HTTP header `Authorization: Bearer ${secret}`
-ALWAYS set a secret if RESTful API is listening on 0.0.0.0
+ALWAYS set a secret if RESTful API is listening on 0.0.0.0
+
+#### default_mode
+
+Default mode in clash, `rule` will be used if empty.
+
+This setting has no direct effect, but can be used in routing and DNS rules via the `clash_mode` rule item.
+
+#### store_selected
+
+!!! note ""
+
+    The tag must be set for target outbounds.
+
+Store selected outbound for the `Selector` outbound in cache file.
+
+#### cache_file
+
+Cache file path, `cache.db` will be used if empty.