Rebase replays a branch's changes on a new base and creates replacement commits. It can keep a review history linear, but it changes identifiers and must be coordinated for shared branches. Confirm that both the upstream change and the feature work survive. A merge also integrates content but produces different history. The tasks ask specifically for replayed feature work, so the check inspects ancestry as well as the files. A feature replay should have the updated main commit as an ancestor and a single-parent feature tip. If the final tip has two parents, you integrated with a merge instead of producing the requested replay.