1 files changed, 1 insertions, 1 deletions
diff --git a/toolkit/components/extensions/parent/ext-contextualIdentities.js b/toolkit/components/extensions/parent/ext-contextualIdentities.js
index c7f28d5e90..c1d6262b6e 100644
--- a/toolkit/components/extensions/parent/ext-contextualIdentities.js
+++ b/toolkit/components/extensions/parent/ext-contextualIdentities.js
@@ -126,7 +126,7 @@ ExtensionPreferencesManager.addSetting(CONTAINERS_ENABLED_SETTING_NAME, {
 this.contextualIdentities = class extends ExtensionAPIPersistent {
   eventRegistrar(eventName) {
     return ({ fire }) => {
-      let observer = (subject, topic) => {
+      let observer = subject => {
         let convertedIdentity = convertIdentityFromObserver(subject);
         if (convertedIdentity) {
           fire.async({ contextualIdentity: convertedIdentity });