Examine source code of Inspector DOM Sidebar

{
  "description": "Adds a new sidebar to the developer tools inspector panel. The sidebar displays the page document as an inspectable object.",
  "manifest_version": 2,
  "name": "devtools-inspector-sidebar",
  "version": "1.0",
  "author": "Nicolas Chevobbe",
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/devtools-inspector-sidebar",
  "permissions": [
    "<all_urls>"
  ],
  "devtools_page": "devtools/devtools-page.html"
}