diff --git a/devtools/projects/shell-browser/src/app/ng-validate.ts b/devtools/projects/shell-browser/src/app/ng-validate.ts
index d7de037380656..6d41ba06c4bc7 100644
--- a/devtools/projects/shell-browser/src/app/ng-validate.ts
+++ b/devtools/projects/shell-browser/src/app/ng-validate.ts
@@ -14,7 +14,9 @@ window.addEventListener('message', (event: MessageEvent) => {
   }
 });
 
-const script = document.createElement('script');
-script.src = chrome.runtime.getURL('app/detect_angular_for_extension_icon_bundle.js');
-document.documentElement.appendChild(script);
-document.documentElement.removeChild(script);
+if (document.contentType === 'text/html') {
+  const script = document.createElement('script');
+  script.src = chrome.runtime.getURL('app/detect_angular_for_extension_icon_bundle.js');
+  document.documentElement.appendChild(script);
+  document.documentElement.removeChild(script);
+}