History of Mark::step 1 change

In crates/backdrop/src/mark.rs, lines 101–107 on 58ac360b334575a55b2149a5dd40b59592da2eee8b6196a3afee51a5c08fdb50. 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 101,107:crates/backdrop/src/mark.rs.