A ChromeDev Tool developer utilizes Google Chrome's built-in development tools to diagnose problems, debug code, and optimize website performance. Their tasks involve inspecting and editing HTML, CSS, and JavaScript, monitoring network activity, optimizing load performance, and assessing runtime bottlenecks. They can also manipulate website elements in real-time, aiding in design and layout. Furthermore, they can assess storage usage, detect memory issues and security vulnerabilities. Proficiency in ChromeDev Tools is essential for web developers as it provides insights into the internal workings of web applications, helping to improve efficiency, performance, and ultimately, user experience.