1 files changed, 1 insertions, 1 deletions
diff --git a/toolkit/components/resistfingerprinting/tests/browser/head.js b/toolkit/components/resistfingerprinting/tests/browser/head.js
index 9d8ec19956..e2fddaecc6 100644
--- a/toolkit/components/resistfingerprinting/tests/browser/head.js
+++ b/toolkit/components/resistfingerprinting/tests/browser/head.js
@@ -54,7 +54,7 @@ function countDifferencesInArrayBuffers(buffer1, buffer2) {
 
 function promiseObserver(topic) {
   return new Promise(resolve => {
-    let obs = (aSubject, aTopic, aData) => {
+    let obs = (aSubject, aTopic) => {
       Services.obs.removeObserver(obs, aTopic);
       resolve(aSubject);
     };