What is the use of the Developer Tools in VS Code?

In mycase, can not find in Toggle Developer Tools from Help, but find CommandPalette(Cmd+P and type '>').

When you select the option Help > Toggle Developer Tools, the Chrome DevTools window should open. Visual Studio Code is built with Electron, which is simply put a wrapper or container for creating desktop applications built with HTML and Javascript.

With this in mind, the Developer Tools can be especially handy if you're debugging or developing plugins, or IDE specifics for Visual Studio Code itself.