DevTools is a suite of tools that lets you inspect and debug the behavior of web applications running on a computer, including web pages, web workers, and extensions.

Use DevTools to inspect and debug the performance of your site, including the rendering and layout of elements, the execution of JavaScript, and network activity.

The Features reference section provides detailed information about each feature, including the performance metrics that it measures and the factors that contribute to those metrics.

The Timeline event reference section provides detailed information about each event type that appears in the Performance panel's Timeline.