diff --git a/.github/workflows/pr-checks.yml b/.github/workflows/pr-checks.yml
index b2ce0a614..2ae059440 100644
--- a/.github/workflows/pr-checks.yml
+++ b/.github/workflows/pr-checks.yml
@@ -128,9 +128,9 @@ jobs:
         working-directory: pr-checks
         run: npx tsx --test
 
-      - name: Run `pr-checks/changenotes.mts` to ensure that all unreleased change notes are valid
+      - name: Run `pr-checks/changenotes.ts` to ensure that all unreleased change notes are valid
         if: ${{ !cancelled() && steps.install-deps.outcome == 'success' }}
-        run: npx tsx pr-checks/changenotes.mts validate
+        run: npx tsx pr-checks/changenotes.ts validate
 
       - name: Verify all Actions use the same Node version
         id: head-version
diff --git a/pr-checks/changenotes.ts b/pr-checks/changenotes.ts
index 58d4cefa1..933d255cd 100755
--- a/pr-checks/changenotes.ts
+++ b/pr-checks/changenotes.ts
@@ -82,9 +82,9 @@ function main(): ExitCode {
 
 function usage(): ExitCode {
   const message =
-    "Usage: changenotes.mts assemble\n" +
-    "       changenotes.mts validate\n" +
-    "       changenotes.mts help";
+    "Usage: changenotes.ts assemble\n" +
+    "       changenotes.ts validate\n" +
+    "       changenotes.ts help";
   console.log(message);
   return ExitCode.Success;
 }