This configuration backend permits one to store part of the configuration in local files. For example you can use this to store secrets outside LLNG configuration.
lemonldap-ng.ini example:
[configuration]
type = Overlay
overlayRealtype = File
overlayDirectory = /var/lib/lemonldap-ng/secrets
# File parameters
dirName = /var/lib/lemonldap-ng/conf
Then store in the overlayDirectory a file for each parameter (filename == keyname)