shell-things/etc/opt/chromium/policies/managed/brave-search.json

{
  "DefaultSearchProviderEnabled": true,
  "DefaultSearchProviderKeyword": "b",
  "DefaultSearchProviderName": "Brave",
  "DefaultSearchProviderNewTabURL": "",
  "DefaultSearchProviderSearchURL": "https://search.brave.com/search?q={searchTerms}",
  "DefaultSearchProviderSuggestURL": "https://search.brave.com/api/suggest?q={searchTerms}",
  "NewTabPageSearchBox": "redirect"
}