Examine source code of Life Clock

{
  "manifest_version": 3,
  "name": "Life Clock",
  "version": "1.0",
  "description": "A 24-hour clock scaled to your lifespan — birth at 00:00, estimated death at 23:59",
  "browser_specific_settings": {
    "gecko": {
      "id": "lifeclock@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  }
}