Examine source code of Twitch Chest getter

{
  "manifest_version": 2,
  "name": "Twitch Chest Collector",
  "version": "1.0",
  "description": "Récupère automatiquement les coffres sur Twitch.",
  "permissions": [
    "https://www.twitch.tv/*",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.twitch.tv/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2625b163-d51e-4c1a-8363-3ba82b0d111e}"
    }
  }
}