Anyone know where in the talk it has the mention of "Debugging tools (mostly!) work well"?

I'm skipping back and forwards through it, but the talk isn't in the same order as this article which is making it very difficult without watching the whole talk from start -> end.

Asking because debugging is a pain point I've been having with Go for a few months, so am surprised to see it described as mostly working well. I'd like to get my debugging experiences to at least that level of "(mostly) working well". :D