The Facebook Pixel Helper is a troubleshooting tool that helps you validate your pixel implementation.
The Facebook Pixel Helper works in the background to look for conversion or Facebook pixels and provide realtime feedback on the implementation. A small number will appear on the Facebook Pixel Helper icon to indicate number of pixel events. When clicked, a panel will expand to show a detailed overview of the page's pixels, including warnings, errors and successes. Learn more about using Facebook pixels here: https://developers.facebook.com/docs/marketing-api/facebook-pixel