In VS Code, simply press <kbd>F5</kbd> (or run `Debug: Start Debugging` from the command palette) and a new window will pop up where you can test the extension.
To debug the internal PDF viewer, select `View LaTeX PDF > View in web browser,` and view a PDF file in Google Chrome. You can debug the viewer with [Chrome DevTools](https://developers.google.com/web/tools/chrome-devtools/) as a general web application.