History of Sky::step 2 changes

In crates/backdrop/src/sky.rs, lines 428–483 on ecac6e8d9b418b87593f8c58c1e36449c8f9fae5fb68a5e4d08e9bb1f8e6e6ab. 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 428,483:crates/backdrop/src/sky.rs.