Examine source code of GPTemail

{
  "name": "GPTEmail",
  "manifest_version": 2,
  "version": "1.0",
  "description": "Uses LLMs to suggest responses to emails.",
  "icons": {
    "32": "icons/32.png",
    "48": "icons/48.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "clipboardWrite"
  ],
  "browser_action": {
    "default_icon": "icons/32.png",
    "default_title": "GPTemail",
    "default_popup": "popup/draft_email.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://mail.google.com/*",
        "*://mail.yahoo.com/*",
        "*://outlook.live.com/*",
        "*://app.hey.com/*"
      ],
      "js": [
        "browser-polyfill.min.js",
        "gptemail.js"
      ]
    }
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+E"
      },
      "description": "Send a 'toggle-feature' event"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{986b40b9-39ef-47fd-b5dc-00d622cfcdb6}"
    }
  }
}