re: what the game actually reads at boot -- config.ini, and which

GameParts exist at all

Q6's second half, advanced but not closed, and the negative is the point.

config.ini is the disc's ONLY config file -- one find over the whole
extract -- and its own Shift-JIS header calls it the "Application /
GamePart initial settings table". Its [SYSTEM] section, which that same
comment says holds what the game and every game part share, is EMPTY. So
the boot order is not in disc-side configuration at all, and that search
space is now closed rather than merely unexplored.

What the file DOES carry is the language: XC_LANGUAGE_* -> eng/jpn/deu/
fra/esp/ita, defaulting to eng. That is the mechanism behind the EN/JP
build pairs in GP_TITLE and the <lang>.pak families -- a question the
corpus had described but never traced to its input.

Then the registry. Pulling every RegisterToFactory diagnostic string
binds 24 of the 29 GamePart ids to a C++ class, and five ids have no
registration site: 1, 2, 16, 18, 28. Id 1 is GP_ADVERTISE_DEMO, which
agrees with what I measured two iterations ago -- the attract loop is the
TITLE replaying ADV.wmv, not a transition into an advertise part. Marked
amber, not green: it is an argument from an error message, not from code.

Two things fall out for Q4: ids 3 and 4 are the same class
(GamePart_SaveLoad, one part with two ids), and the menu buttons' ids now
match the executable's own class names rather than a list of table names.
Still a name match, one level closer to the code.

What is still missing is the transitions themselves, and I say so: the
manifest gives the boot-side assets, config.ini the language, the
registry which parts exist. What decides to advance is in
GamePart_Title's code and that dig has not been started.

docs/re/data/gamepart-class-ids.txt

@@ -0,0 +1,29 @@
+GamePart ids bound to a C++ class by the executable's own registration strings
+(24 strings, 24 distinct ids)
+
+    0  GamePart_Title
+    3  GamePart_SaveLoad
+    4  GamePart_SaveLoad
+    5  GamePart_Extras
+    6  GamePart_MovieTheater
+    7  GamePart_MissionSelect
+    8  GamePart_Options
+    9  GamePart_Movie
+   10  GamePart_Bunk
+   11  GamePart_ReadyRoom
+   12  GamePart_Hangar
+   13  GamePart_Arsenal
+   14  GamePart_PilotLog
+   15  GamePart_System
+   17  GamePart_MainGame
+   19  GamePart_PauseMenu
+   20  GamePart_StageClear
+   21  GamePart_MissionLog
+   22  GamePart_GameOver
+   23  GamePart_Debriefing
+   24  GamePart_Dialog
+   25  GamePart_Tutorial
+   26  GamePart_ChallengeMission
+   27  GamePart_Leaderboard
+
+ids 0..28 with NO registration string: [1, 2, 16, 18, 28]