diff --git a/.eslintignore b/.eslintignore
index 129fefda3b6c..c1af7f7e3d23 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -42,7 +42,7 @@ browser/components/enterprisepolicies/schemas/schema.jsm
 browser/components/translation/cld2/
 # Screenshots is imported as a system add-on and has
 # their own lint rules currently.
-# browser/extensions/screenshots/
+browser/extensions/screenshots/
 # generated or library files in pocket
 browser/components/pocket/content/panels/js/tmpl.js
 
diff --git a/browser/extensions/screenshots/test/browser/injection-page.html b/browser/extensions/screenshots/test/browser/injection-page.html
index cf26a2f5bbac..c7579aa8b5ad 100644
--- a/browser/extensions/screenshots/test/browser/injection-page.html
+++ b/browser/extensions/screenshots/test/browser/injection-page.html
@@ -17,7 +17,7 @@ let callback = function(mutationsList, observer) {
     }
   }
 };
-var observer = observer();
+
 observer = new MutationObserver(callback);
 observer.observe(document.body, {childList: true});
 </script>