See where each character on the screen came from in code.
The extension is currently in beta and won't work on all pages.
1. Go to a page you want to inspect
2. Click the FromJS icon next to the URL bar
3. Wait for the page to load
4. Click "Show FromJS Inspector" button in the top right corner of the page
Report problems here: https://github.com/mattzeunert/fromjs/issues