diff --git a/packages/flutter/lib/src/services/system_chrome.dart b/packages/flutter/lib/src/services/system_chrome.dart
index 40809b9c0d..2188754c63 100644
--- a/packages/flutter/lib/src/services/system_chrome.dart
+++ b/packages/flutter/lib/src/services/system_chrome.dart
@@ -109,6 +109,8 @@ class SystemUiOverlayStyle {
   /// The brightness of the system navigation bar icons.
   ///
   /// Only honored in Android versions O and greater.
+  /// When set to [Brightness.light], the system navigation bar icons are light.
+  /// When set to [Brightness.dark], the system navigation bar icons are dark.
   final Brightness? systemNavigationBarIconBrightness;
 
   /// The color of top status bar.