0.0.0.0 is an DNS Changer. It's different from 1.1.1.1: Faster & Safer Internet which only uses CloudFare DNS server.
This DNS changer connects to fastest DNS server to create betternet:
- CloudFare DNS server 1.1.1.1
- Google DNS server 8.8.8.8
- And many more

Benefits:
- DNSpipe can unblock sites, 3G 4G wifi booster
- Net Booster for PUBG
- Better net connection, web surfing experience
- Create high-speed internet

Android offers no options to change DNS servers for mobile network 2G/3G/4G.