I listened to part. 2 following part. 1! It was great to learn various ways to understand and optimize performance with developer tools. :) Based on the lecture, I'm trying to use the Performance tab in practice, but it's still not easy to see the internal data. It's hard to find out what specific function is working. Haha. But I'm going to try to get into the habit of continuously looking for and checking! It was fun to learn in detail things I had overlooked. Thank you!