Examine source code of UnQuote for Gmail

{
  "name": "UnQuote for Gmail",
  "description": "Unquote text of previous mails from the reply",
  "version": "1.0.5",
  "manifest_version": 3,
  "icons": {
    "128": "assets/icon.png"
  },
  "background": {
    "page": "background/index.html"
  },
  "action": {
    "default_title": "UnQuote for Gmail",
    "default_popup": "popup/index.html"
  },
  "permissions": [
    "storage"
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "content_scripts": [
    {
      "matches": [
        "*://mail.google.com/*"
      ],
      "js": [
        "cs/index.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a78a25b6-cbeb-11ed-afa1-0242ac120002}",
      "strict_min_version": "109.0"
    },
    "safari": {
      "strict_min_version": "15.4"
    }
  }
}