diff --git a/src/bg/user-script-detect.js b/src/bg/user-script-detect.js
index 50de884cf..accc768c5 100644
--- a/src/bg/user-script-detect.js
+++ b/src/bg/user-script-detect.js
@@ -49,7 +49,6 @@ function detectUserScriptOnHeadersReceived(details) {
   let encoder = new TextEncoder();
   let filter = browser.webRequest.filterResponseData(details.requestId);
 
-  let userScriptUrl = details.url;
   let userScriptContent = '';
 
   filter.ondata = event => {