repo.files re-read and re-parsed the B-card baseline for every delta check-in — 79% of the mint phase on pkgsrc. Repository.filesMemo takes a caller-owned BaselineMemo keyed by artifact name; consecutive deltas over one baseline borrow the parsed manifest and read nothing. On a 30k-file history of 300 deltas, source enumeration went from 10s to 0.3s and the conversion from 13.5s to 3.7s, every check-in hash identical. The memo holds a heap entry with a stable address; the optional-by-value form did not persist under ReleaseFast. Closes zit#167. check-in: c80728261e user: dmestas tags: trunk