Examine source code of History AutoDelete

{
  "manifest_version": 2,
  "name": "History AutoDelete",
  "version": "1.1",
  "description": "Automatically delete browsing history after a specified time.",
  "permissions": [
    "history",
    "storage"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    },
    "default_title": "History AutoDelete",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/icon48.png"
  },
  "web_accessible_resources": [
    "content.js"
  ],
  "applications": {
    "gecko": {
      "id": "59879942285f44ca9e9d8fda699c4714@your-domain.com"
    }
  }
}