re: the Arsenal develop economy, and the save blob's index space (first 32 confirmed)

GP_HANGAR_ARSENAL.pak's screen config points at weapon.tbl (item ids, in the
8-category display order) and strings.tbl (names, descriptions, and a
"Conditions to obtain" block per item). The id run No_Equipment .. Wep_83 is
exactly 54 long -- the save blob's length -- and all 60 conditions blocks are
extracted to a CSV: gates are stage completion, a predecessor item, or an ace
kill; costs run 3000-350000 P, and 20 items cost nothing once gated (which is
why items the player never bought read as Developed).

Predicting the save state from those conditions -- before looking at the blob --
says exactly six items are developable here, and the blob's six 2s sit on those
six, in weapon.tbl order, at indices 1/5/10/12/27/31. With the four obtained
items and the differential's own two transitions that is twelve concordances
over indices 0-31, nothing fitted. Broad Sword SG1 at index 5 needed scrolling
the GUN list to see, which is the only one the first screenshots missed.

The tail is NOT settled and is marked so: the Tomahawk is weapon.tbl index 38
and the screen shows it Developed, but blob[38] = 0, and the other tail 4s
(33/39/45/46/47) land on items the Arsenal shows as locked -- the SPECIAL tab is
entirely empty. A +1 shift does not repair it either. Settling it needs a second
development in a late category, which needs a mission payout.

Also recorded: IDXD string pools dedupe repeated values, so only the first
record of a table can be read from the token stream -- record 2 shows just its
unique values, record 6 no cost at all.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/re/structures/savegame-format.md

@@ -131,15 +131,16 @@ three-state progression *locked → developable → developed*, and the blob is
 Arsenal's development state, not a bitmask of owned weapons (a bitmask could not
 represent the middle state).
 
-Two things this does **not** settle, and should not be written as if it did:
+**Which item each index is** was chased separately and is **half settled** — see
+[the Arsenal develop economy](../arsenal-develop-economy.md). In short: the index
+space is the `WEAPONS` id list in `GP_HANGAR_ARSENAL.pak :: eng\weapon.tbl`, whose
+`No_Equipment … Wep_83` run is exactly 54 long; twelve independent concordances
+confirm indices **0–31** (including all six `2`s, predicted from the disc's own
+"Conditions to obtain" text before the blob was looked at), while the tail from
+index 33 on contradicts the screen and is left ❔.
+
+One more thing this does **not** settle, and should not be written as if it did:
 
-- **Which item each index is.** The index space is 54 wide; the player-arsenal id
-  lists in `GP_HANGAR_ARSENAL.pak` union to 35 distinct weapon ids, so the blob is
-  not indexed by that list. MG I is at index **1**, not 0, even though it is the
-  first row of the first weapon type — so index 0 is something already developed
-  that the GUN list does not show first. **NEEDS-HUMAN / needs another
-  differential**: develop a second item in a *different* category and see which
-  index moves.
 - **Whether the +1 on the clear ratio is per item.** One data point. If it is
   per item, the ratio is a *collection* metric and not a stage metric, which
   matters because it is one of the three numbers the Details panel shows and it