Both are alternate-baseline choices inside the shipped merge machinery, per merge-flags contract B-merge-30..40 (which lifts merge.md's v1 non-goal); the flagless zit merge NAME surface is byte-identical (B-merge-31 re-asserts it).

- --cherrypick REV: three-way with base = REV's primary parent, other = REV, current = checkout (apply REV's own changes). --backout REV: base = REV, other = REV's primary parent (reverse REV). Same classifyFile/applyMerge engine; a root REV yields an empty side; zero entries refuse (B-merge-39). Flags are mutually exclusive and reject an extra positional / dirty tree. - A cherrypick/backout commit stays SINGLE-parent (REV is never a merge parent) and mints exactly one artifact 4.7.14 Q card (Q +rev / Q -rev), cleared one-shot; a plain merge keeps its two-token P card and empty Q. - The pending op is a new checkout special_op field (4th TLV, no default, threaded everywhere); undo serializes it (journal fmt v1->2) so undo unwinds a pending cherrypick/backout (B-merge-35).

B-merge-1..29 e2e all still pass. 1675 unit + 362 e2e green; fmt clean. Follow-up: B-merge-41 (zit info Q-card render line) deferred — its pinned text was absent from the plan; the Q card is already readable via zit artifact. check-in: 20bf0a31c6 user: dmestas tags: cli