Examine source code of yahoo-dictionary-en-tw

{
  "manifest_version": 2,
  "name": "yahoo-dictionary-en-tw",
  "version": "1.1",
  "description": "Adds yahoo dictionary (en -> tw) as a search engine.",
  "icons": {
    "32": "icons/yahoo-32.png"
  },
  "chrome_settings_overrides": {
    "search_provider": {
      "favicon_url": "https://tw.dictionary.search.yahoo.com/favicon.ico",
      "is_default": false,
      "keyword": "yd",
      "name": "Yahoo Dictionary (en -> tw)",
      "search_url": "https://tw.dictionary.search.yahoo.com/search",
      "search_url_get_params": "p={searchTerms}"
    }
  }
}