The grants part grants on them, the tool runner appends and snapshots on
them and the bus module creates the history over them, so the three read
one contract (the lead's ruling on issue 1966 B1; ADR 0597 §8, §9).
ADR 0597 §9 and the lead's Q1 path: one ledger credential per module
assignment, minted by the vault like every kind; the grants part's copy
of buscompose gains the same kind alike (D5b).