History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 659–679 on 4e2cad00a484ec04fc5edd10a0af8637f0ae6490552573304680eaed36906a89. 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 659,679:crates/hub/src/diffusion.rs.