The Elements Tab is the primary source of information for anything related to the DOM of the inspected page.
The Timelines Tab contains all of the performance profiling and introspection tools provided by Web Inspector, organized into different timelines each with their own area of interest and specialized interface.
After the position and size of each DOM node has been calculated, they are drawn onto a series of surfaces called layers, which are then composited in a particular order to produce the resulting appearance of the web page.
The Audit Tab contains collections of audits, each of which can be run against the inspected page to check for incorrect DOM structure, missing accessibility attributes, correct design system rules, and much more.
The Sources Tab is the one-stop shop for all things related to the inspected target’s resources, including dynamic resources from things like XMLHttpRequest or fetch.
When trying to inspect the DOM/CSS of any page, often the first step is finding the specific DOM node in the DOM Tree of the Elements Tab.
Console Object API
Console Command Line API
One of the most useful parts of Web Inspector is being able to generate interactive visualizations of any value in the Console.