Examine source code of Wandering Enderman

{
  "manifest_version": 3,
  "name": "Wandering Enderman",
  "version": "1.0.0",
  "description": "Spawns an Enderman that roams the page, snatching elements for a short trip before dropping them back.",
  "browser_specific_settings": {
    "gecko": {
      "id": "wandering-enderman@local",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scripts/enderman.js"
      ],
      "css": [
        "styles/enderman.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "frames/*.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}