@testing-library/user-event simulates real user interactions within React component tests. It extends @testing-library/dom by providing functions that mimic browser events more accurately, such as typing, clicking, and hovering. This library facilitates robust and realistic testing by triggering event sequences that closely resemble user behavior, uncovering potential issues not always caught by simpler event firing. It helps ensure your application responds correctly to user actions, leading to more dependable and user-friendly software.