[VictorLiwentao]

Change and scope

One-flag follow-up to #3349 under priority revision 6, card p104-side-correction. That census already shows the basis head meets the target final on only 4 of 208 matched flags. This package pins one of the other 204: flag 2 (X1 → Y84, basis head 488).

On the published 4,058-event word:

• X1 starts at [488] and drops 488 at transport event 494
• every annotated Y84 frame avoids 488
• the Y84 final excludes 488
• no event names both endpoints

The published channel therefore cannot chronologically host a basis-head coefficient or dirty-restore that source line into the matched target along this flag's geometry.

Scoped obstruction. No new kappa. Selected κ stays 0.001672660197076918. A changed schedule that does host the head is outside this package.

Result

Package: research/p104-absent-head-flag2-audit/.
Tip: 06b130eda28e638c58b333346f85b187e8012f25.
Base: 6f100d4bb5083f8c35d96fd95a539811c62f245c.

Validation

python3.12 -I -B research/p104-absent-head-flag2-audit/verify.py
python3.12 -I -O -Werror -B research/p104-absent-head-flag2-audit/verify.py
python3.12 -I -O -Werror -B research/p104-absent-head-flag2-audit/independent.py
python3.12 -I -O -Werror -B research/p104-absent-head-flag2-audit/test_package.py
python3.12 -B scripts/research_package.py --package research/p104-absent-head-flag2-audit

Expected:

PASS_P104_ABSENT_HEAD_FLAG2 flag=2 head=488 target_hosting=0 drop_event=494 no_new_kappa
PASS_P104_ABSENT_HEAD_FLAG2_INDEPENDENT flag=2 head=488 target_hosting=0 drop_event=494 no_new_kappa
PASS_P104_ABSENT_HEAD_FLAG2_TESTS groups=6
PASS_REGISTERED_RESEARCH_PACKAGE research/p104-absent-head-flag2-audit outcome=completed

Default verify is read-only. Admission uses need() and still fires under -O.

Overlap and credit

Closest prior: #3349 for the 4/208 final-head census. This package does not reopen that full restoration count, the #3259 cut, #3386, #3374, or the merged readout series through #2883.

Credit Nick Petalas / #2981, jwr404 / #3242, and the reviewed #1991 channel. Prepared by Wentao Li (VictorLiwentao, @Is__Victor) with substantial AI assistance, under Apache-2.0.