Changes touching this path

• a test can no longer mutate the engine past every named face, because with_repo_mut is deleted and the 27 fixtures that reached through it each name the state they fabricate, while the one that was re-deriving load_shared_lineage by hand calls it (#1447) 9c3573f6 · dbf3dbe6…

Renames are not followed. loot's tree maps a path to an address, so a rename is a delete and an add. This list is the history of the name, not of the bytes.