diff --git a/src/libcamera/control_ids_rpi.yaml b/src/libcamera/control_ids_rpi.yaml
index a8615112..aca023d7 100644
--- a/src/libcamera/control_ids_rpi.yaml
+++ b/src/libcamera/control_ids_rpi.yaml
@@ -183,4 +183,14 @@ controls:
         \sa SyncMode
         \sa SyncReady
         \sa SyncTimer
+
+  - ControlId:
+      type: int64_t
+      direction: out
+      description: |
+        This is the sequence number of the request whose control list has
+        just been applied. Controls normally take several frames to apply,
+        so the number here will refer to a request submitted a number of
+        frames earlier.
+
 ...