See enumerators Group.Category, Object.Category, and Spot.Category for further reference.
Function also works with Unit, Weapon, Static Object, Scenery Object, Airbase. When used with any of these objects the category returned is related to the Object.Category.
Group Functions: isExist, activate, destroy, getCategory, getCoalition, getName, getID, getUnit, getUnits, getSize, getInitialSize, getController
Spot Functions: createInfraRed, destroy, getCategory, getPoint, setPoint, getCode, setCode