$conf_d and $unbound_conf_d are not documented and unclear how they differ beyond their location

[arusso]

I'm trying to understand the difference between the undocumented $conf_d and $unbound_conf_d parameters of the unbound class. Neither seems to be used anywhere outside of ensuring directory ownership (but not included in the configuration by default), and in the case of the $unbound_conf_d directory, you can also ensure the directory is purged of unmanaged configurations.

Can we get these parameters documented based on the intended usage?

[Valantin]

I'm not sure, but a possible explaination was:
unbound_conf_d is the default directory for many OS packages with precondigured configuration, the module purge the content.
conf_d I assume is a directory with not managed configuration we want to use, the module create it by default but not include it in the configuration