Examine source code of Duolingo Images

{
  "description": "Adds images to Duolingo sentences, to improve your learning experience",
  "manifest_version": 2,
  "name": "Duolingo Images",
  "version": "1.0",
  "homepage_url": "https://github.com/mcmaartenz/fx-duolingo-image",
  "content_scripts": [
    {
      "matches": [
        "*://*.duolingo.com/*"
      ],
      "js": [
        "main.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1bd7ed8b-19c5-4512-9db6-82f67e74d323}"
    }
  }
}