Examine source code of alt. browser extension

{
  "manifest_version": 3,
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "version": "0.0.1",
  "action": {},
  "description": "__MSG_extensionDescription__",
  "permissions": [
    "storage",
    "tabs",
    "scripting"
  ],
  "background": {
    "scripts": [
      "src/pages/background/index.js"
    ],
    "type": "module"
  },
  "host_permissions": [
    "http://*/**/*",
    "https://*/**/*"
  ],
  "icons": {
    "128": "icon-128.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "assets/js/*.js",
        "assets/fonts/*.woff2",
        "icon-128.png",
        "icon-34.png",
        "/content-iframe.html",
        "src/pages/content-iframe/index.js"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "kholid060@gmail.com"
    }
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  }
}