History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 460–480 on ed3a36b6414c28f923e71384afe4dc78a7541ea98e95a2af640cfd46ed92fd77. 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 460,480:crates/hub/src/diffusion.rs.