BinaryPathWML
From The Battle for Wesnoth Wiki
the toplevel [binary_path] tag
This tag is used to recognize more than one directory as containing images, music, and sound. It only has one key:
- path: a directory. When an image is not found it the normal images directory, it will be looked for in path/images. Similarly, music will be looked for in path/music, and sound in path/sound.
Notice that path is still relative to the main Wesnoth directory.
[binary_path] should only be used where necessary. For example a multiplayer era should have its [binary_path] inside an #ifdef MULTIPLAYER instead of outside it in order to avoid possible clashes with single-player content.
Example
To enable the game to find images, sounds and music in the add-on MyAddOn:
[binary_path] path=data/add-ons/MyAddOn [/binary_path]
When the game looks for an image units/humans/footman.png, it'll now be able to find and use the file MyAddOn/images/units/humans/footman.png.