FORMAT U Format List
 Town Buildings

? - unknown for me.
+ - upgraded version or version for upgraded dwelling support
value in parenthesis is town type
(x) means all towns
Dword Bit reference Structure index Buildings
0 00000001 0 Magic Guild Lvl 1
0 00000002 1 Magic Guild Lvl 2
0 00000004 2 Magic Guild Lvl 3
0 00000008 3 Magic Guild Lvl 4
0 00000010 4 Magic Guild Lvl 5
0 00000020 5 Tavern
0 00000040 6 Shipyard(0,4,7,8) - only if present
0 00000080 7 Fort
0 00000100 8 Citadel
0 00000200 9 Castle
0 00000400 10 Village
0 00000800 11 Town Hall
0 00001000 12 City Hall
0 00002000 13 Capitol
0 00004000 14 Marketplace
0 00008000 15 Resource Silo
0 00010000 16 Blacksmith
0 00020000 17 Lighthouse(0)
Mystic Pond(1)
Artifact Merchants(2,5,8)
?(3)
Cover of Darkness(4)
Escape Tunnel(6)
Cage of Warlords(7)
0 00040000 18 Griffin Bastion(0)
Miner's Guild(1)
Sculptor's Wings(2)
Birthing Pools(3)
Unearthed Graves(4)
Mushroom Rings(5)
Mess Hall(6)
Captain's Quarters(7)
Garden of Life(8)
0 00080000 19 Griffin Bastion+(0)
Miner's Guild+(1)
Sculptor's Wings+(2)
Birthing Pools+(3)
Unearthed Graves+(4)
Mushroom Rings+(5)
Mess Hall+(6)
Captain's Quarters+(7)
Garden of Life+(8)
0 00100000 20 Ship at the Shipyard - only if Shipyard present
0 00200000 21 Stables(0)
Fountain of Fortune(1)
Lookout Tower(2)
Brimstone Storm clouds(3)
Necromancy amplifier(4)
Mana Vortex(5)
Freelance Guild(6)
Glyphs of Fear(7)
Magic University(8)
0 00400000 22 Brotherhood of the Sword(0)
Treasure(1)
Library(2)
Castle Gate(3)
Skeleton Transformer(4)
Portal of Summoning(5)
Ballista Yard(6)
Blood Obelisk(7)
?(8)
0 00800000 23 ?(0,1,4,7,8)
Wall of Knowledge(2)
Order of Fire(3)
Battle Scholar Academy(5)
Hall of Valhalla(6)
0 01000000 24 ?(0,2,4,5,6,7,8)
Dendroid Saplings(1)
Cages(3)
0 02000000 25 ?(0,2,4,5,6,7,8)
Dendroid Saplings+(1)
Cages+(3)
0 04000000 26 Grail
0 08000000 27 Houses near city hall
0 10000000 28 Houses near municipal
0 20000000 29 Houses near Capitol
0 40000000 30 Dwelling 1
0 80000000 31 Dwelling 2
1 00000001 32 Dwelling 3
1 00000002 33 Dwelling 4
1 00000004 34 Dwelling 5
1 00000008 35 Dwelling 6
1 00000010 36 Dwelling 7
1 00000020 37 Dwelling 1+
1 00000040 38 Dwelling 2+
1 00000080 39 Dwelling 3+
1 00000100 40 Dwelling 4+
1 00000200 41 Dwelling 5+
1 00000400 42 Dwelling 6+
1 00000800 43 Dwelling 7+

The internal structure keeps a two 32 bit values (that you can set or get with B1 command) and every bit there means one structure. Then if the bit is set, the structure may be built only after that structure (that bit is set). If the bit is 0, there is not dependence.
So all mentioned in B2 structure bits are set to 1. Others are set to 0. If you want to modify the existing sequence, you need to use B1/?$/?$ syntax to get values, set or remove bits that you want and use B1/$/$ to set it back.

Also, if you make this structure depends on X structure and X structure in its turn depends on Y structure, so this structure will depends not only on X but also on Y structure and you need not to set Y structure in the command.

Source: ChangeLog0.1