Examine source code of Widget Burger

{
  "manifest_version": 2,
  "name": "Widget Burger",
  "description": "A dynamic new tab page with local layouts and configurable widgets.",
  "version": "1.4.0",
  "icons": {
    "16": "/icon-16.png",
    "32": "/icon-32.png",
    "48": "/icon-48.png",
    "128": "/icon-128.png"
  },
  "permissions": [
    "cookies",
    "identity",
    "storage",
    "https://widgetburger.com/*"
  ],
  "oauth2": {
    "client_id": "434236056149-rr1540suqnqf23l0uaobre7ghul8rlhj.apps.googleusercontent.com",
    "scopes": [
      "https://www.googleapis.com/auth/calendar.readonly"
    ]
  },
  "optional_permissions": [
    "https://air-quality-api.open-meteo.com/*",
    "https://api.frankfurter.app/*",
    "https://*.elewave.work/*",
    "https://earthquake.usgs.gov/*",
    "https://hacker-news.firebaseio.com/*",
    "https://date.nager.at/*",
    "https://api.open-meteo.com/*",
    "https://api.wikimedia.org/*",
    "https://api.sunrise-sunset.org/*",
    "https://nominatim.openstreetmap.org/*",
    "https://www.googleapis.com/*",
    "topSites"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@elewave.work",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo",
          "locationInfo"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "options_ui": {
    "open_in_tab": false,
    "page": "options.html"
  }
}