History of Sky::step 2 changes

In crates/backdrop/src/sky.rs, lines 428–483 on ec84907043c2ad9321efa120752a37be37c17620bacb7b4119ba57ed0644d524. 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.