Geoscape Files

These files are used by the Geoscape portion of the game.

ACTS.DAT
AKNOW.DAT
ALIEN.DAT - Contains Alien activity in Countries and areas, for graphs
ASTORE.DAT - Has the info on aliens in alien containment.
BASE.DAT - Has all of the base layout and contents information, radar scanning abilities and other base information.
BGLOB.DAT
BPROD.DAT - List of goods being produced.
CRAFT.DAT - Has all the craft info, weapons, fuel, damage and items onboard. Also stores UFO information, although information is handled differently from friendly aircraft.
DIPLOM.DAT - Diplomacy info.
FACIL.DAT - Info on facilities you can build.
IGLOB.DAT - Date and time.
INTER.DAT
LEASE.DAT
LIGLOB.DAT - Money!
LOC.DAT - Location of bases on the planet as well as other things like ships. Basically anything that is an icon on the Geoscape.
MISDATA.DAT
PRODUCT.DAT - Info on things you can produce.
PROJECT.DAT - These are things you are researching.
PURCHASE.DAT - Info on stuff you can buy.
RESEARCH.DAT - Completed research.
SAVEINFO.DAT - Name of the saved game.
SOLDIER.DAT - Data about the soldiers.
TRANSFER.DAT - Personnel and goods being transferred.
UIGLOB.DAT
UP.DAT - UFOpaedia info.

Battlescape Files

These files are created and used by the tactical portion of the game. They are only created if th game is saved while in the battlescape.

MAP.DAT - Stores tile information for the whole map. Basically all static structures, such as trees, walls, floors and furniture.
OBPOS.DAT - Stores all the objects that your soldiers can pick up (guns, corpses, etc).
ROUTES.DAT - Stores nodes for soldier and alien spawn points, also acts as waypoints for AI pathfinding.
GEODATA.DAT
SEEMAP.DAT - Fog of war overlay.
SOURCEMP.DAT and TERMP.DAT - Both files are light source overlays. Ones for mobile light sources (i.e. your soldiers) and the other is for ambient (or fixed) lighting.
SMOKEBIT.DAT - Smoke particles and fire patches on the map.
SMOKEREF.DAT - Smoke particles and fire patches on the map.
UNITPOS.DAT - Controls every section of a small unit or a large unit in the map. Works hand in hand with unitref.dat. Controls ownership, visibility, whether the unit is under temporary mind control, etc.
UNITREF.DAT - Contains the primary stats for all units in combat. X-Com owned soldiers in this file are virtual copies of the soldiers in soldier.dat. Works very closely with unitpos.dat.
WGLOB.DAT - Map information, like map dimensions. Might also include the tileset and other map information. Stores the current turn and the actual turns, used mainly for testing grenade detonation conditions.