Examine source code of Wikipedia-

{
  "manifest_version": 2,
  "name": "Wikipedia-FR",
  "description": "Rechercher sur Wikipedia (FR)",
  "version": "1.0",
  "applications": {
    "gecko": {
      "strict_min_version": "55.0",
      "id": "{f93001c2-0a7d-4761-9bb9-fe33152219b9}"
    }
  },
  "chrome_settings_overrides": {
    "search_provider": {
      "name": "Wikipedia-FR",
      "search_url": "https://fr.wikipedia.org/w/index.php?title=Spécial:Recherche&search={searchTerms}",
      "keyword": "wfr",
      "favicon_url": "https://fr.wikipedia.org/static/favicon/wikipedia.ico",
      "is_default": false,
      "encoding": "UTF-8"
    }
  }
}