As a part of your driving test, you may have had to complete an emergency stop. This helps the examiner to assess your reaction times, as well as your awareness of your surroundings. It’s a manoeuvre that we all have to be able to complete in order to safely use the roads, though hopefully we’ll never actually need to use it!
That said, there’s a good chance that you haven’t performed an emergency stop since passing your test. And if you’re still learning, you might want a virtual practice run to sharpen your skills.