Examine source code of Daily Challenges Tab

{
  "manifest_version": 2,
  "name": "Daily Challenges Tab",
  "version": "1.0",
  "description": "Displays a daily challenge or motivational task every time a new tab is opened.",
  "icons": {
    "48": "icon.png"
  },
  "chrome_url_overrides": {
    "newtab": "popup.html"
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f7325db8-1d45-4362-8256-03c620ac5c19}"
    }
  }
}