I wondered this too. So I will try to dig it up in the text files. Because (probably as you want) I want to add text to the normally non-playable factions and a good map instead of the 'normal' map. Strangely, 2 factions (the Macedonians and one other, can't remember which) already have text for them, but not a detailed map.
Looks like they wanted to add the factions as a patch later on to encourage late buyers?