The bit at +0x04 was recorded as a real field with its meaning "not
diagnosed", noting ptlogo_back2eff is 0x8830 "despite its name". That note
rested on a size match -- and its size is ambiguous, which is the trap
this corpus already records.
First, a sound attribution. T8aD headers appear in the bundle in RATC
CHILD ORDER, verified on GP_TITLE build 4 against an independent property
-- each header's decoded dimensions versus the dimensions the named child
should have: 18 of 18 match, 0 mismatches. Two of those eighteen share a
size (ptlogo_back2eff and ptlogo_back2eff5, both 1133x280), so a size-keyed
lookup cannot separate them; ordering can. Index 12 is back2eff5 (0x8832,
bit set), index 14 is back2eff (0x8830, bit clear). The documented
counterexample is real and correctly attributed -- now on evidence.
Two candidate meanings tested and refuted:
bit <=> name contains "eff" REFUTED: ptlogo_back2eff is an eff
name with the bit clear. All 10
bit-set sprites are eff names, so
the implication holds one way only.
bit <=> the element is transient REFUTED: pteff03/pteff03a carry the
bit and run to t=250, ramping to
a=255 and holding.
Up close, the exception pair differs in two header words: +0x04
0x8832/0x8830 and +0x08 0x8083/0x8081 -- layer keys 32899 and 32897. They
are NOT duplicates: their alpha summaries agree to one decimal (4.5%
opaque, 86.7% clear, mean 19.3) but a pixel compare gives max abs diff 21.
Two renditions of one image at one size, which is why the summaries were
not trusted.
Still not diagnosed, and said so -- but the search space is two smaller
and the attribution beneath it is now sound.
METHOD: T8aD headers sit in child order, use that not the size; and
identical summary statistics are not identical data.
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