devtools_page

"devtools_page": "devtools/my-page.html"

Use this key to enable your extension to extend the browser's built-in devtools.

This key is defined as a URL to an HTML file. The HTML file must be bundled with the extension, and the URL is relative to the extension's root.

The use of this manifest key triggers an install-time permission warning about devtools. To avoid an install-time permission warning, mark the feature as optional by listing the "devtools" permission in the optional_permissions manifest key.

See Extending the developer tools to learn more.