We recently dropped a new feature that automatically detects intervals in your bike workout session chart if you have a power meter. You can see this by looking at a bike workout with power and can mouse over an interval to show details
and click to zoom into the interval.
We would love any feedback on this new feature so we can further improve it and eventually roll it out to other sports. You can learn more on how it works in this interview between @Prof and @Stef, who created the feature.