# Devtools [Chrome Docs](https://developer.chrome.com/docs/extensions/mv3/devtools/) • [Firefox Docs](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/devtools_page) ## Filenames ## Definition ```html ``` ## Adding UI Elements Chrome extensions allow you to add panels and side panes to the devtools window. ![DevTools window showing Elements panel and Styles sidebar pane.](https://developer.chrome.com/static/docs/extensions/how-to/devtools/extend-devtools/image/devtools-window-showing-e-9051f7f0347cd_1920.png) See the WXT's examples for a full walkthrough of extending the devtools window: