Examine source code of Clickster

{
  "manifest_version": 2,
  "name": "Clickster",
  "version": "2.0.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d9a80c5d-e4ea-4d11-8437-aedf73f2028b}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Auto-click any element — or a point on a canvas/game — at a rate you choose, with multiple targets at once.",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png",
    "128": "icons/128.png"
  },
  "browser_action": {
    "default_icon": "icons/48.png",
    "default_title": "Clickster",
    "default_popup": "popup/popup.html"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "optional_permissions": [
    "*://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  }
}