Examine source code of Nether Calculator

{
  "manifest_version": 3,
  "name": "Nether Calculator",
  "version": "1.0.0",
  "description": "MC overworld ↔ nether X/Z converter (vanilla 8:1 scale). Client-side only. Unofficial; not affiliated with Mojang or Microsoft.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_title": "Nether calculator",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "permissions": [],
  "host_permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "nether-calculator@orefinder.io",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}