History of sigv4 1 change

In crates/hub/src/backups.rs, lines 457–482 on 15d3f6f7871b9ba24296599a30f4188cde40d8831dff7bdaad16c717bfadd9f4. 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 457,482:crates/hub/src/backups.rs.