One bit per log frame in .zit-cache/dispositions: crosslink-relevant or not. A full derive consults it and never reconstructs the file blobs and SUBMANIFEST tree nodes that were most of a wide store's walk; the walk distills a fresh map either way. Same trust tier as the log-scan index: self-checksummed, keyed to a validated log prefix, stamped with the shun fingerprint, absent on any doubt. pkgsrc submanifest cold derive 302 s to 22 s; a consuming derive's body is byte-identical, pinned by test. check-in: a18d2edd67 user: dmestas tags: trunk