Next DevTools is a free Chrome add-on developed by CraftValue that provides useful features for analyzing NextJS applications. This add-on includes a badge icon that indicates when the page props for a given page are too heavy in NextJS, helping developers optimize their apps for better performance. The badge icon is displayed only during the first page load, allowing developers to quickly identify potential issues.

In addition, Next DevTools adds a "NextJS DevTools" panel to the Chrome DevTools when using the `Link` component. This panel provides convenient access to various tools and functionalities specifically designed for NextJS development.

Next DevTools is a valuable tool for NextJS developers who want to optimize their applications and improve performance. With its intuitive interface and helpful features, it simplifies the process of analyzing and optimizing NextJS apps.