Examine source code of GPT emailer

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{afe834e3-e4f7-40eb-a438-bcb2d5a13f33}"
    }
  },
  "name": "GPT-3 emailer",
  "description": "A simple extension that replies to email using GPT-3.",
  "version": "1.3",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  }
}