Examine source code of MarketButler

{
  "manifest_version": 3,
  "name": "MarketButler",
  "version": "0.1.21",
  "browser_specific_settings": {
    "gecko": {
      "id": "marketbutler@labelbutler.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Aggregate seller offers across all your Cardmarket wantlists in one view.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage",
    "unlimitedStorage"
  ],
  "host_permissions": [
    "*://www.cardmarket.com/*"
  ],
  "background": {
    "scripts": [
      "src/background/index.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.cardmarket.com/*"
      ],
      "js": [
        "src/content/index.js"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "*://www.cardmarket.com/*/Offers/Singles*"
      ],
      "js": [
        "src/content/tooltip-main.js"
      ],
      "run_at": "document_idle",
      "world": "MAIN"
    },
    {
      "matches": [
        "*://www.cardmarket.com/*/*/Products/*",
        "*://www.cardmarket.com/*/*/Cards/*"
      ],
      "js": [
        "src/content/product-page.js"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "*://www.cardmarket.com/*/ShoppingCart"
      ],
      "js": [
        "src/content/cart-page.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "action": {
    "default_popup": "src/popup/index.html",
    "default_title": "MarketButler",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png"
    }
  },
  "options_ui": {
    "page": "src/options/index.html",
    "open_in_tab": true
  }
}