This version is for the 0.7 Stable release of Cataclysm: Bright Nights. To use this, copy over the Arcana_BN folder into data/mods.
If you are using experimental Bright Nights, it is recommended you update from the main page using the "download zip" option within the green "code" button, and copy the Arcana_BN folder into data/mods folder.
Likewise, if you are using experimental DDA, use the Arcana folder from the master branch.