History of checkpoint 2 changes

In crates/hub/src/tlog.rs, lines 773–778 on a9088323c39024e0c4098547ac234cd71589e7a4af0c6b92fd6a343648e85ff2. 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 773,778:crates/hub/src/tlog.rs.