diff --git a/F1.md b/F1.md
index a89b96c5..3825c668 100644
--- a/F1.md
+++ b/F1.md
@@ -12,23 +12,26 @@ It's completely optional and clients may choose to fulfill only some of these ta
 
 ## Tags
 
-| Tag                | Type                               | Description                                                                             |
+| Name               | Value type                         | Description                                                                             |
 | ---                | ----                               | -----------                                                                             |
 | `background-color` | hex value                          | To be used by clients when displaying the user profile page                             |
 | `foreground-color` | hex value                          | Idem                                                                                    |
 | `background-music` | URL                                | Music that optionally plays when the profile is opened                                  |
 | `priority_kinds`   | stringified kind number (variadic) | Kinds to be displayed by default in the user profile page (rather than `kind:1` always) |
+| `custom`           | string name, then value            | An arbitrary field to be displayed along with the profile                               |
 
 ## Example
 
-```json
+```yaml
 {
   "kind": 19999,
   "tags": [
     ["background-color", "#1a1a2e"],
     ["foreground-color", "#eee444"],
     ["background-music", "https://example.com/music/profile-theme.mp3"],
-    ["priority_kinds", "20", "30023", "21", "10009"]
+    ["priority_kinds", "20", "30023", "21", "10009"],
+    ["custom", "favorite fruit", "banana"],
+    ["custom", "pets?", "no"]
   ],
   // ...other fields
 }