PR #127: Mutation diff mode

Agent Instructions

Click a suite to see its builds. Example suite for ef1685db :

https://staging.nix-ci.com/gh:NorfairKing:sydtest/refs%2Fpull%2F127%2Fmerge/ef1685dbfff2e952be912b7fbc207aa1e601460a

For more instructions, fetch https://staging.nix-ci.com/instructions .