diff --git a/files/en-us/mozilla/add-ons/webextensions/debugging_(before_firefox_50)/index.html b/files/en-us/mozilla/add-ons/webextensions/debugging_(before_firefox_50)/index.html
index e49cb3f40a409b1..099495e17d807e6 100644
--- a/files/en-us/mozilla/add-ons/webextensions/debugging_(before_firefox_50)/index.html
+++ b/files/en-us/mozilla/add-ons/webextensions/debugging_(before_firefox_50)/index.html
@@ -221,7 +221,7 @@ <h4 id="Select_the_popup's_frame">Select the popup's frame</h4>
 
 <pre>moz-extension://&lt;some-uuid&gt;/path/to/your-popup.html</pre>
 
-<p>{{EmbedYouTube("/9jdHDCKIN-U")}}</p>
+<p>{{EmbedYouTube("9jdHDCKIN-U")}}</p>
 
 <p>Now the scope of the toolbox is the popup. In the Inspector, you can examine and modify the popup's HTML and CSS. In the Debugger, you can search for any scripts loaded into the popup, and set breakpoints in them.</p>