ALL T8aD sprites (top-level + RATC children): 21184
upper half of the +0x08 word is zero        : 21184/21184
distinct u16 keys at +0x0A                  : 216
keys in more than one pak family            : 68/216 = 31%
keys confined to GP_MAIN_GAME_2D            : 52/216
the six language 2D paks have identical key sets: True (6 paks)

keys per family:
                   GP_BUNK.pak:  16 keys  8000..a110
              GP_CHALLENGE.pak:   9 keys  8000..9200
    GP_DEBRIEFING_PILOTLOG.pak:  17 keys  8200..9900
                 GP_DIALOG.pak:  22 keys  8100..f102
               GP_GAMEOVER.pak:   6 keys  d840..d862
         GP_HANGAR_ARSENAL.pak:  20 keys  8000..9412
            GP_LEADERBOARD.pak:  14 keys  8000..f100
           GP_MAIN_GAME_2D.pak:  72 keys  0000..9820
            GP_MISSION_LOG.pak:   5 keys  a400..a420
         GP_MISSION_SELECT.pak:  13 keys  8300..9820
          GP_MOVIE_THEATER.pak:   7 keys  8300..9122
                GP_OPTIONS.pak:  21 keys  0000..b900
             GP_PAUSE_MENU.pak:   8 keys  8020..a112
             GP_READY_ROOM.pak:  45 keys  0000..9fff
              GP_SAVE_LOAD.pak:  27 keys  8300..f100
            GP_STAGE_CLEAR.pak:  12 keys  8200..9112
                 GP_SYSTEM.pak:   7 keys  a010..a112
                  GP_TITLE.pak:  28 keys  8000..c150
               GP_TUTORIAL.pak:   5 keys  8210..8312
                       deu.pak:   5 keys  8000..8010
                       eng.pak:   5 keys  8000..8010
                       esp.pak:   5 keys  8000..8010
                       fra.pak:   5 keys  8000..8010
                       ita.pak:   5 keys  8000..8010
                       jpn.pak:   5 keys  8000..8010

commonest 12 keys: [('8000', 1768), ('8100', 1524), ('9230', 1454), ('9400', 857), ('9220', 776), ('9402', 720), ('8010', 689), ('9110', 527), ('9100', 467), ('8900', 450), ('8400', 426), ('a100', 423)]