Why does my SSH Known Hosts have hashes instead of hostnames or IPs?

I have a host behind a dynamic IP, so I used to have a script that would add its address to my .ssh/known_hosts file, recently though it seems like something has changed. My file looks like its been attacked by the hash monster: |1|Du0QWjqCUrdRK/pnE0PTww2O2Zk=|O31W+SPPLr9+sj1m1K7MfEb+xUQ= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILUT1234567Xu2vvCE1likgUSOXLzEV123456783asaA |1|K3vgE86MLJTHx8W2sPv1cgP4DI0=|Jattsr5sEW443bnyMKT6W0Noc+k= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILUT1234567Xu2vvCE1likgUSOXLzEV123456783asaA |1|UlAukzqGavXZvRtMzjvXmHoVeAQ=|0JVjq7YSFulCHmkF46VFwMV/ZBY= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILUT1234567Xu2vvCE1likgUSOXLzEV123456783asaA 1. Is there anyway to go back to the old, less secure method? 2. How can I easily create entries in this hashed format? (I want to write a script to tell ssh that any ip in the 10.0.0.0/24 range is should match the given fingerprint.)