Browser Developer Tools are built-in features in web browsers that help developers inspect and debug websites. They allow users to view the underlying code of a webpage, including HTML, CSS, and JavaScript. This makes it easier to identify issues, test changes, and optimize performance. These tools typically include a console for running JavaScript commands, a network monitor to track resource loading, and an element inspector to modify the appearance of a page in real-time. Most modern browsers, like Google Chrome, Mozilla Firefox, and Microsoft Edge, offer these tools, making web development more accessible.