diff --git a/gio/gdbus-2.0/codegen/codegen.py b/gio/gdbus-2.0/codegen/codegen.py
index a8174ce6b..01c53674f 100644
--- a/gio/gdbus-2.0/codegen/codegen.py
+++ b/gio/gdbus-2.0/codegen/codegen.py
@@ -2835,7 +2835,7 @@ class CodeGenerator:
                 )
             if m.unix_fd:
                 self.outfile.write(
-                    " * @out_fd_list: (out) (optional): Return location for a #GUnixFDList or %NULL to ignore.\n"
+                    " * @out_fd_list: (out) (optional) (nullable): Return location for a #GUnixFDList or %NULL to ignore.\n"
                 )
             self.outfile.write(
                 self.docbook_gen.expand(
@@ -2913,7 +2913,7 @@ class CodeGenerator:
                 )
             if m.unix_fd:
                 self.outfile.write(
-                    " * @out_fd_list: (out): Return location for a #GUnixFDList or %NULL.\n"
+                    " * @out_fd_list: (out) (optional) (nullable): Return location for a #GUnixFDList or %NULL.\n"
                 )
             self.outfile.write(
                 self.docbook_gen.expand(
diff --git a/gio/gdbusconnection.c b/gio/gdbusconnection.c
index 3c82fd8de..086960daf 100644
--- a/gio/gdbusconnection.c
+++ b/gio/gdbusconnection.c
@@ -6867,7 +6867,7 @@ g_dbus_connection_call_with_unix_fd_list (GDBusConnection     *connection,
 /**
  * g_dbus_connection_call_with_unix_fd_list_finish:
  * @connection: a #GDBusConnection
- * @out_fd_list: (out) (optional): return location for a #GUnixFDList or %NULL
+ * @out_fd_list: (out) (optional) (nullable): return location for a #GUnixFDList or %NULL
  * @res: a #GAsyncResult obtained from the #GAsyncReadyCallback passed to
  *     g_dbus_connection_call_with_unix_fd_list()
  * @error: return location for error or %NULL
@@ -6914,7 +6914,7 @@ g_dbus_connection_call_with_unix_fd_list_finish (GDBusConnection  *connection,
  * @timeout_msec: the timeout in milliseconds, -1 to use the default
  *     timeout or %G_MAXINT for no timeout
  * @fd_list: (nullable): a #GUnixFDList or %NULL
- * @out_fd_list: (out) (optional): return location for a #GUnixFDList or %NULL
+ * @out_fd_list: (out) (optional) (nullable): return location for a #GUnixFDList or %NULL
  * @cancellable: (nullable): a #GCancellable or %NULL
  * @error: return location for error or %NULL
  *
diff --git a/gio/gdbusproxy.c b/gio/gdbusproxy.c
index e00289991..02d6fb75d 100644
--- a/gio/gdbusproxy.c
+++ b/gio/gdbusproxy.c
@@ -3065,7 +3065,7 @@ g_dbus_proxy_call_with_unix_fd_list (GDBusProxy          *proxy,
 /**
  * g_dbus_proxy_call_with_unix_fd_list_finish:
  * @proxy: A #GDBusProxy.
- * @out_fd_list: (out) (optional): Return location for a #GUnixFDList or %NULL.
+ * @out_fd_list: (out) (optional) (nullable): Return location for a #GUnixFDList or %NULL.
  * @res: A #GAsyncResult obtained from the #GAsyncReadyCallback passed to g_dbus_proxy_call_with_unix_fd_list().
  * @error: Return location for error or %NULL.
  *
@@ -3095,7 +3095,7 @@ g_dbus_proxy_call_with_unix_fd_list_finish (GDBusProxy    *proxy,
  * @timeout_msec: The timeout in milliseconds (with %G_MAXINT meaning
  *                "infinite") or -1 to use the proxy default timeout.
  * @fd_list: (nullable): A #GUnixFDList or %NULL.
- * @out_fd_list: (out) (optional): Return location for a #GUnixFDList or %NULL.
+ * @out_fd_list: (out) (optional) (nullable): Return location for a #GUnixFDList or %NULL.
  * @cancellable: (nullable): A #GCancellable or %NULL.
  * @error: Return location for error or %NULL.
  *