It's an internet privacy company that offers a variety of products to help protect your privacy, most notably a browser extension and it's own private search engine.
Based on the search results, it appears that the DuckDuckGo browser does not use Chromium. Instead, it uses Apple's WebKit rendering system , which is the same rendering engine used by Apple's Safari browser. DuckDuckGo has chosen to use WebKit instead of Chromium or Blink, the fork of WebKit used by Chromium-based browsers.