Mozilla rr is a tool that you can use to record, replay, and debug applications. The main idea of Mozilla rr is to help you catch non-trivial bugs. The rr tool records a program execution. So later, you can replay the failing execution in the debugger as many times as you need. From the Run menu in the gutter, select Record and Debug <configuration_name> . Note: Mozilla rr is available only on Linux machines. Read more about Mozilla rr on the official Mozilla rr site.