Examine source code of Scryfall Art Crop

{
  "manifest_version": 2,
  "name": "Scryfall Art Crop",
  "version": "1.0",
  "description": "Adiciona um link para o corte de arte do Scryfall",
  "icons": {
    "48": "icons/crop-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://scryfall.com/card/*"
      ],
      "js": [
        "art-crop.js"
      ]
    }
  ]
}