Examine source code of Startpage - POST

{
  "manifest_version": 2,
  "name": "Startpage search engine (POST request)",
  "description": "It adds the Startpage search engine to firefox using the POST request",
  "version": "1.1",
  "applications": {
    "gecko": {
      "strict_min_version": "57.0",
      "id": "{cf853ed2-8325-48e7-8408-972d78cdfcac}"
    }
  },
  "chrome_settings_overrides": {
    "search_provider": {
      "name": "Startpage search engine POST request",
      "search_url": "https://www.startpage.com/sp/search",
      "search_url_post_params": "q={searchTerms}",
      "suggest_url": "https://www.startpage.com/suggestions",
      "suggest_url_post_params": "q={searchTerms}",
      "keyword": "sp",
      "favicon_url": "https://www.startpage.com/sp/cdn/images/startpage-magnifying.svg",
      "is_default": true
    }
  }
}