Dragon Runner is a type of machine that is used to find, fix, and keep track of bugs in a computer program. It looks for instances of the same problem happening in different parts of the program, and then tries to figure out how to fix it. Once it finds a way to fix something, Dragon Runner will remember what it did and can use that same fix if it finds the same problem again. This helps programmers and developers make sure their programs work the way they expect them to.