History of sign_challenge 2 changes

In src/cli/identity.rs, lines 918–939 on c96354484bd96287c36037349c6bd02e0018bf790bfc04663f8c4efb894d0c13. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 918,939:src/cli/identity.rs.