The port agent pointed out that forced_backdrop_necessity.rs collapsed
sprite_layer_key (a u16 read from the T8aD header, decoded) with
implied_layer_key (this crate's table of positions MEASURED in the running
game), and that 'has its own key' therefore reads as file-backed when it is
not. Splitting them is stronger than either of us stated:
read from the T8aD header: 0
implied (measured): 14 10x pfbase.tbm, 4x palogo_eff0.prm
nothing at all: 66 62 decided, 4 inert
Zero. There is no instance on the disc where a forced element also carries a
file-read layer key, so this rule has never been checked against a decoded
field -- there is no case where both can speak. That is what a keyless-element
fallback necessarily looks like, but it removes a check a reader would assume
exists.
Also corrects something I said to the port and had wrong. 'None of the 18 is
evidence for the rule in any direction' conflated two questions. Whether the
rule changes the composite: no, the sort already had the key. Whether the rule
gets the RIGHT answer: yes, and the 14 implied keys are measured positions, so
this is the rule agreeing with the oracle -- its only external corroboration,
and there are 14 instances of it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
