There are two locations where configuration files are stored. This may look confusing at first, the reason is that we try to support both sparse zones and full zones as good as possible. Remember that in a sparse root environment /opt is shared from the global zone. As a rule of thumb configuration files which are specific to a zone are kept in /etc/opt/csw which is also generally preferred (these are in fact most of the configuration files), whereas /opt/csw/etc is used for configuration files which are globally set. Some packages honour both locations, where the global /opt/csw/etc is read first and can be customized by /etc/opt/csw, but this is specific to the package as not all upstream software allows this easily.
There are some exceptions like Apache, where the configuration files are historically in /opt/csw/apache2/etc, but these are likely to go away some time.
pkgutil can use two configuration files:
This may seem confusing, the reason why there are two is that it is possible to run OpenCSW in a sparse root environment where /opt is not writable. In this scenario you use configurations in /opt/csw/etc for global settings and /etc/opt/csw for zone-specific setting. Both pkgutil.conf are identical on installation with all configuration options commented out, so you can just pick one for now. As a rule of thumb it is recommended to prefer the more prominent /etc/opt/csw.
Configuration files are usually shipped as template with a .CSW suffix which is copied during installation to the native name without the suffix. This file is meant to be user-adjustable. On package deinstallation or update the template is deinstalled whereas the configuration file without suffix is kept unless it hasn’t been modified.