Examine source code of NewTabBlackClock

{
  "manifest_version": 2,
  "name": "NewTabBlackClock",
  "version": "0.3resigned1",
  "description": "New tab override to black-BG with clock",
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "permissions": [
    "topSites"
  ],
  "applications": {
    "gecko": {
      "strict_min_version": "54.0a1",
      "id": "{b02a713e-9343-4b77-87e9-267f82d457c7}"
    }
  }
}