Examine source code of Duolingo Solution Viewer

{
  "name": "Duolingo Solution Viewer",
  "version": "4.19.3",
  "description": "Provides access to the lists of solutions for Duolingo's translation / listening challenges, and restores the correction of typos.",
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.duolingo.com/*"
      ],
      "js": [
        "src/content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "assets/css/ui.css",
    "src/observer.js",
    "src/ui.js"
  ],
  "icons": {
    "16": "icons/icon_16.png",
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png",
    "256": "icons/icon_256.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{aadcf03b-d15c-4419-9c88-79b45a15b9d8}"
    }
  }
}