The millenaire/ directory is auto-deployed by Millénaire on each new version of the mod, erasing all changes made to it.

If you want to add content to Millénaire, copy the files to the corresponding directory in millenaire-custom, 
which is not touched by updates.

All files present in millenaire-custom will replace the file present in millenaire, except for :
- Language files
- blocklist.txt and itemlist.txt
- tradedgoods.txt for each cultures

The content of those files are instead added to that of the corresponding file in millenaire.

Most of Millénaire's specific content directories, for example:
- goals/genericcrafting/
- cultures/<culture>/buildings/
- cultures/<culture>/villagers/

support putting content in subdirectories. This has no effect on how files behave and is purely for organisation purpose.
One small exception: buidings added to cultures/<culture>/buildings/lone/ will not be added to villages, as they are intended for custom buildings.