Examine source code of MasterDuelMeta Assistant

{
  "manifest_version": 3,
  "version": "2.0",
  "name": "MasterDuelMeta Assistant",
  "description": "This extension is used to export Yu-Gi-Oh! Decks from Masterduelmeta.com to www.db.yugioh-card.com and vice versa.",
  "content_scripts": [
    {
      "matches": [
        "https://www.db.yugioh-card.com/*",
        "https://*.masterduelmeta.com/*"
      ],
      "js": [
        "index.js"
      ]
    }
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@masterduelmeta.com"
    }
  }
}