To check a web page for issues, install the extension and load the page you want to check. Click the extension icon (a check sign super imposed on the globe to look like all’s well in the world). The Basic tab tells you what errors it has detected on the web page. Click the Advanced tab to check where those issue appear on the page. Clicking on the Advanced tab will reload the page and highlight each area with a number. The tab displays the issues along with the number of occurrences on the page and each number that appears on the page corresponds to one of the issues.
The extension identifies ‘potential’ things that might cause a compatibility issue, developers of course can’t start using it as their trouble shooting guidebook but it’s a quick way to get an overview and it saves you time that you’d have spent doing the task manually.