I'd like to assign some factions buildings not on the original list - theatres for Rome, city plumbing for Carthage, that sort of thing. So far I've managed to:

edit export_descr_buildings
edit export_descr_buildings_enums
edit text\export_buildings
copy, paste and rename the little construction pictures (although the Egyptian elite cavalry stables refuse to change to a hippodrome).

So far so good, but what about descr_settlement_plan? The entries in this file have me totally flummoxed, as there seem to be multiples for each building. Do I need to alter anything here?