Examine source code of ChatGPT Timestamp

{
  "manifest_version": 3,
  "name": "ChatGPT Timestamp",
  "version": "0.2.4",
  "browser_specific_settings": {
    "gecko": {
      "id": "chatgpt-timestamp@example.com",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Displays timestamps for ChatGPT messages",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon-16.png",
      "48": "icon-48.png",
      "128": "icon.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://chat.openai.com/*",
        "https://chatgpt.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "world": "MAIN"
    }
  ],
  "permissions": [
    "activeTab",
    "scripting"
  ]
}