Examine source code of New-Free-sidebar

{
  "description": "Integrates a new sidebar into the developer tools inspector panel. This sidebar showcases the page document as an inspectable object.",
  "manifest_version": 2,
  "name": "New-Free-sidebar",
  "version": "1.2",
  "author": "Nicolas Chevobbe",
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/devtools-inspector-sidebar",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "js/injected-script.js"
  ],
  "permissions": [
    "<all_urls>",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "activeTab",
    "cookies",
    "downloads",
    "scripting",
    "notifications",
    "contextMenus"
  ],
  "devtools_page": "devtools/devtools-page.html",
  "browser_specific_settings": {
    "gecko": {
      "id": "{b686f58b-2bbf-46af-8e60-67596609ae89}"
    }
  }
}