Examine source code of Recent Tabs History

{
  "manifest_version": 2,
  "name": "Recent Tabs History",
  "version": "1.0",
  "description": "Shows the 10 most recently closed tabs and allows you to clear recent history",
  "permissions": [
    "tabs",
    "sessions",
    "storage",
    "history"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4c9c6842-7afd-4e19-9d2a-e0f68fe1eea3}"
    }
  }
}