You’ve downloaded it.
Now add it to Chrome.

Seeing code files is normal. This folder is the extension’s installation package. Opening popup.html or a JavaScript file does not install the extension.

1. Extract the ZIP first

   On Windows, right-click the downloaded ZIP and choose Extract All → Extract. On Mac, double-click the ZIP. Keep the extracted folder somewhere you can find it.

2. Open Chrome’s extensions page

   Copy chrome://extensions into the address bar in Google Chrome and press Enter. Turn on Developer mode at the top right.

3. Load the whole folder

   Click Load unpacked. Select the extracted folder with manifest.json directly inside it, then click Select Folder. Choose the folder, not the ZIP or an individual file.

4. Pin Second Opinion

   Click Chrome’s puzzle-piece icon. Pin Second Opinion — Evidence Screen. You should now see our icon in the toolbar.

Try your first search

Open ChatGPT, Claude, or a regular webpage. Select one complete factual claim, click the Second Opinion toolbar icon, then choose Find evidence. You can also paste a claim directly. Nothing is searched until you click that button.

The results are research candidates to read, not a guarantee that the claim is true. Open original sources or use the website for on-device model comparison.

Already have an older version?

Replace the old files in your installation folder with this extracted package. At chrome://extensions, click the reload icon on Second Opinion’s card. Keep the installation folder: Chrome continues to load the files from there.

Need help?

Manifest missing: choose the inner folder that contains manifest.json.
No selection: paste your claim; Chrome settings and some PDF pages restrict capture.
Developer mode disabled by your organization: use the website instead.