Examine source code of dark-newtab

{
  "manifest_version": 2,
  "name": "dark-newtab",
  "version": "0.0.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "dark-newtab@wesleyac.com"
    }
  },
  "permissions": [
    "tabs"
  ],
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  }
}