mangos/mangos — comment on commit 69c1fe555acab09594cc2709fe077b05874d8ed0
File: sql/updates/11926_01_mangos_creature_template.sql line 3
By Tasssadar:

Its hex mask.
0x01 - ground
0x02 - water
0x04 - air

(0x01 | 0x02) == 0x03 - ground and water
(0x01 | 0x02 | 0x04) == 0x07 - ground, air and water