Examine source code of Arvutitark Enhanced

{
  "name": "Arvutitark Enhanced",
  "description": "Enhances the user experience of arvutitark.ee",
  "version": "0.0.3",
  "content_scripts": [
    {
      "matches": [
        "https://arvutitark.ee/*"
      ],
      "run_at": "document_start",
      "js": [
        "content/index.js"
      ],
      "css": [
        "content/style.css"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{927726e9-561f-48bd-977e-771387a61a4d}",
      "strict_min_version": "57.0"
    }
  },
  "manifest_version": 2
}