Devices may publish to their own out ports' messages (a level set on the device itself)

backend/tests/api/routes/test_devices.py

@@ -639,10 +639,11 @@ def test_a_devices_own_ports_publish_through_a_lock(
 ) -> None:
     """An ``in`` port is the device's own sensor, which a dashboard lock is not about.
 
-    An ``out`` port is the device following a message, so it reads and does
-    not write, and only an ``in`` port's name opens the artifact upload. A
-    value published on a bound port is the device node's, whatever the device
-    says it is from.
+    An ``out`` port is the device following a message, which it publishes too
+    when set on the device itself (a panel's brightness on its config page).
+    Only an ``in`` port's name opens the artifact upload. A value published on
+    a bound ``in`` port is the device node's, whatever the device says it is
+    from.
     """
     _dashboard_with(client, superuser_token_headers, "panel_io_locked", PANEL_WIDGETS)
     _publish_settings(
@@ -690,7 +691,7 @@ def test_a_devices_own_ports_publish_through_a_lock(
         client.post(
             f"{messages}/porch.backlight", headers=panel_headers, json={"value": 50}
         ).status_code
-        == 403
+        == 200
     )
     assert (
         client.get(