Sentry is used for capturing runtime errors and providing additional features such as performance monitoring and release health. In a recent project, the author used Sentry to track down deprecated code paths during a large code refactoring project. The refactoring involved replacing icons in an application with a new system based on React components. The process was challenging due to the use of property spreading in many parts of the application, which made it difficult to track down dynamic call sites. To overcome this, Sentry's ability to capture exceptions and provide context was utilized. By using Sentry, the author was able to identify and fix remaining call sites, ultimately allowing the old paths to be removed safely. The experience highlighted the benefits of using Sentry not only for error tracking but also for tracking down hard-to-find issues during code refactoring.