Bug 1909692 - [devtools] Show a toggle in the experimental preferences popup to enable the JS Tracer. r=devtools-reviewers,nchevobbe

Differential Revision: https://phabricator.services.mozilla.com/D217586

devtools/client/devtools-experimental-prefs.js

@@ -28,6 +28,10 @@ const PREFERENCES = [
     "Enable bfcache navigation in parent process (requires Fission and involve " +
       "more top level target switching",
   ],
+  [
+    "devtools.debugger.features.javascript-tracing",
+    "Enable the JavaScript tracer. (You need to restart Firefox / the Browser Toolbox to apply this setting)",
+  ],
 ];
 
 /**