From a quick glance:
1) Desktop browser is an electron app with ad tracking injected into your app via http://cdn.brave.com/ (via https://sonobi.com/welcome/index.php which promises "EFFECTIVELY PLAN AND SOURCE MARKETING OPPORTUNITIES WITH QUALITY AND VIEWABILITY FROM PREMIUM PUBLISHERS"
2) iOS browser is a fork of Firefox iOS - https://github.com/mozilla/firefox-ios
3) Android browser is a fork of https://play.google.com/store/apps/details?id=com.linkbubble...