We still have to do the final task of ZHF, which has to wait for the very last minute, and that’s to mark every package (with in reason for evaluation) that is failing to build as broken ZERO Hydra Failures 20.03 · Issue #80379 · NixOS/nixpkgs · GitHub.
Edit: I’m now thinking I should make it a separate bug outside ZHF to add in the milestone as a blocker Mark failing to build packages in 20.03 as broken · Issue #83805 · NixOS/nixpkgs · GitHub