diff --git a/justfile b/justfile
index 05bf28cf25cf5..7e592ef2367e4 100755
--- a/justfile
+++ b/justfile
@@ -137,7 +137,7 @@ test-transform *args='':
 # `just submodules` also does this, but this runs faster. Useful when working on transformer.
 update-transformer-fixtures:
   cd tasks/coverage/babel && git reset --hard HEAD && git clean -f -q
-  node tasks/transform_conformance/update_fixtures.js
+  node tasks/transform_conformance/update_fixtures.mjs
 
 # Install wasm-pack
 install-wasm:
diff --git a/tasks/transform_conformance/package.json b/tasks/transform_conformance/package.json
index 16224f15eb7cb..d04c9d7e5d0c5 100644
--- a/tasks/transform_conformance/package.json
+++ b/tasks/transform_conformance/package.json
@@ -2,7 +2,6 @@
   "name": "transform_conformance",
   "version": "0.0.0",
   "private": true,
-  "type": "module",
   "scripts": {
     "vitest": "vitest"
   },
diff --git a/tasks/transform_conformance/update_fixtures.js b/tasks/transform_conformance/update_fixtures.mjs
similarity index 100%
rename from tasks/transform_conformance/update_fixtures.js
rename to tasks/transform_conformance/update_fixtures.mjs