Using the Long Task Timeline is a great way to identify potential issues with JavaScript performance. We updated the visual representation and categorisation of tasks to make it more clear.
See all the long task warnings and blocking scripts.
The Long Task Timeline showcases all long task warnings and blocking times in the lifespan of the main thread activity. This means that you can not only inspect tasks that contribute to Total Blocking Time (defined between First Contentful Paint and Time to Interactive boundaries) but other long tasks on the main thread that don’t fall in this category.