diff --git a/packages/dev/optimize-locales-plugin/LocalesPlugin.d.ts b/packages/dev/optimize-locales-plugin/LocalesPlugin.d.ts
index 733429f4d86..f7d23082b0c 100644
--- a/packages/dev/optimize-locales-plugin/LocalesPlugin.d.ts
+++ b/packages/dev/optimize-locales-plugin/LocalesPlugin.d.ts
@@ -25,7 +25,7 @@ type TurbopackOptionsList = readonly [TurbopackOptions, ...TurbopackOptions[]];
 
 type TurbopackRule = {
   condition?: TurbopackCondition;
-  loaders: [{loader: string; options: {locales: readonly string[]}}];
+  loaders: [{loader: string; options: {locales: string[]}}];
   as: '*.js';
 };