diff --git a/scripts/migrate-fx140/is-esmified.js b/scripts/migrate-fx140/is-esmified.js
index dd33fdf453..7bbe1799b6 100755
--- a/scripts/migrate-fx140/is-esmified.js
+++ b/scripts/migrate-fx140/is-esmified.js
@@ -34,6 +34,7 @@ function generateESMURIMap(jsm_map) {
 
 function isESMifiedSlow(resourceURI) {
   if (resourceURI.endsWith('.jsm')) {
+    console.log(resourceURI.includes('/zotero/'))
     if (resourceURI.includes('/zotero/')) {
       return { result: true, jsms: [resourceURI.replace('.jsm', '.mjs')] };
     } else {
diff --git a/scripts/migrate-fx140/migrate.py b/scripts/migrate-fx140/migrate.py
index 56ed798b55..081b6c3c3d 100755
--- a/scripts/migrate-fx140/migrate.py
+++ b/scripts/migrate-fx140/migrate.py
@@ -664,12 +664,12 @@ def try_rename_components_conf(command_context, path, jsm_name, esm_name):
 
 
 def esmify_name(name):
-    return re.sub(r"\.(jsm|js|jsm\.js)$", ".sys.mjs", name)
+    return re.sub(r"\.(jsm|js|jsm\.js)$", ".mjs", name)
 
 
 def esmify_path(jsm_path):
     jsm_name = jsm_path.name
-    esm_name = re.sub(r"\.(jsm|js|jsm\.js)$", ".sys.mjs", jsm_name)
+    esm_name = re.sub(r"\.(jsm|js|jsm\.js)$", ".mjs", jsm_name)
     esm_path = jsm_path.parent / esm_name
     return esm_path
 
@@ -713,7 +713,7 @@ def find_jsm_uri(jsm_path):
 
 
 def rename_single_file(command_context, vcs_utils, jsm_path, summary):
-    """Rename `jsm_path` to .sys.mjs, and fix references to the file in build
+    """Rename `jsm_path` to .mjs, and fix references to the file in build
     and test definitions."""
 
     def info(text):
diff --git a/scripts/migrate-fx140/utils.js b/scripts/migrate-fx140/utils.js
index 801aab62af..9e275dca3b 100755
--- a/scripts/migrate-fx140/utils.js
+++ b/scripts/migrate-fx140/utils.js
@@ -68,7 +68,11 @@ function isString(node) {
 const jsmExtPattern = /\.(jsm|js|jsm\.js)$/;
 
 function esmifyExtension(path) {
-  return path.replace(jsmExtPattern, ".sys.mjs");
+  if (path.includes('/zotero/')) {
+    return path.replace(jsmExtPattern, ".mjs");
+  } else {
+    return path.replace(jsmExtPattern, ".sys.mjs");
+  }
 }
 
 // Given possible member expression, return the list of Identifier nodes in