This is very good solution I encountered a similiar problem and came up with the same solution. I wanted to add a modular EDU mod and a custom leaderhead for Ethiopia I created 2 files: /Mod/Assets/Modules/Default_CIV4CivilizationInfos.xml /Mod/Assets/Modules/Default_CIV4CivilizationsSchema.xml and updated in /Mod/Assets/Modules/Default_CIV4CivilizationInfos.xml to These files are exact copies from the /Assets/XML/Civilizations/ folder. The reason I put them in Modules was in case you don't want a /Mod/Assets/XML folder in your mod (although I still needed one for Audio & Diplomacy). In Default_CIV4CivilizationInfos.xml I made the changes, for example Ethiopia: overwrite: add: I use this file stritcly for changes to the Firaxis civs. Added civs still get their own ***_CIV4CivilizationInfos.xml in Custom Civilizations. Of course this does not make it Plug & Play, but it is a clean solution for now.