diff --git a/packages/flutter/lib/src/gestures/converter.dart b/packages/flutter/lib/src/gestures/converter.dart
index 5a5fcdd7c40..21095d1e580 100644
--- a/packages/flutter/lib/src/gestures/converter.dart
+++ b/packages/flutter/lib/src/gestures/converter.dart
@@ -304,11 +304,6 @@ abstract final class PointerEventConverter {
                 scale: datum.scale,
               );
             case ui.PointerSignalKind.unknown:
-            default: // ignore: no_default_cases, to allow adding a new [PointerSignalKind] - PointerStylusAuxiliaryAction
-            // TODO(louisehsu): remove after landing engine PR https://github.com/flutter/engine/pull/39637
-              // This branch should already have 'unknown' filtered out, but
-              // we don't want to return anything or miss if someone adds a new
-              // enumeration to PointerSignalKind.
               throw StateError('Unreachable');
           }
         }).whereType<PointerEvent>();