Examine source code of RevealURL

{
  "name": "RevealURL",
  "version": "2.0.1",
  "description": "Validate any shortURL with RevealURL ",
  "permissions": [
    "contextMenus",
    "activeTab",
    "notifications",
    "storage"
  ],
  "background": {
    "scripts": [
      "assets/js/background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "assets/images/icon_16.png",
      "32": "assets/images/icon_32.png",
      "48": "assets/images/icon_48.png",
      "128": "assets/images/icon_128.png"
    }
  },
  "icons": {
    "16": "assets/images/icon_16.png",
    "32": "assets/images/icon_32.png",
    "48": "assets/images/icon_48.png",
    "128": "assets/images/icon_128.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "id@revealurl"
    }
  }
}