Old World has a console that can be accessed by LeftCtrl + LeftShift + ` (That key left of the 1 key upper left on ENG keyboard) That shortcut can be modified in Options/Screens
Console is mostly a developer tool and its commands are listed in Old World/support site
Console uses numbers as IDs for game elements. Those cannot be accessed directly from game files and require you to have DEBUG MODE on (only available now from TEST build). Any ID refers to its location in the in game arrays. This is why it doesn't exist it the xmls. The only way to find IDs is to have debug text turned on in game options. In the console you would refer to them as a number only.
The only Ids that you can somehow deduce are playerID as in Single Player you are always PlayerID 0. So, depending on how many AI you have in the game, they will get attributed by the game an ID starting with 1.
addmoney 100 0 will give you 100 gold, you cheater !