Examine source code of SteamChecker

{
  "manifest_version": 3,
  "version": "1.0.0.0",
  "version_name": "1.0.0",
  "name": "SteamChecker",
  "description": "Grays-out & highlights owned/wishlisted Steam games on Humble Bundle",
  "icons": {
    "16": "src/assets/icons/icon-16.png",
    "48": "src/assets/icons/icon-48.png",
    "128": "src/assets/icons/icon-128.png"
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "https://www.foxslash.com/apps/steamchecker/*"
  ],
  "content_scripts": [
    {
      "js": [
        "assets/content.ts-loader-CDQca05a.js"
      ],
      "matches": [
        "https://www.humblebundle.com/*"
      ],
      "css": [
        "assets/content-CY8JYVGA.css"
      ]
    }
  ],
  "action": {
    "default_icon": "src/assets/icons/icon.png",
    "default_popup": "src/pages/popup/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@steamchecker",
      "strict_min_version": "109.0"
    }
  },
  "web_accessible_resources": [
    {
      "matches": [
        "https://www.humblebundle.com/*"
      ],
      "resources": [
        "assets/messages-pwnBscFK.js",
        "assets/content.ts-CfJfSHwP.js"
      ],
      "use_dynamic_url": true
    }
  ]
}