After removal of nethserver-sogo zzz_SOGo.conf.rpmsave and a by a template overwritten (harmless) SOGo.conf are kept in /etc/httpd/conf.d/. Effectively disabling all apache configuration for the Application.
Worked on this a bit more and I can not Agree. It makes no sense to keep a apache configuration file after a nethserver module is removed.
Dug in to two packages who install their own configuration, webtop-dav and rouncubemail.
webtop5-webdav.conf is completely static and roundcubemail.conf gets overwritten by templates.
If nethserver-webtop is removed and then SOGo is installed it breaks card / caldav for support SOGo due to the apache configuration staying behind.
As said before removing nethserver-roundcubemail has no effect, the service is still available after removal. Situation actually gets worse as we lose control over this configuration because it does not get updated (as example) if you change the trussed networks.
IMHO nethserver / e-smith shall be in control over the (content of) the loaded apache configuration files for nethserver modules.
This leeds me to a more radical idea:
After removal of a nethserver module no apache configuration file for this module shall be (re)loaded.
Until package removal is improved: It should be considered bad practice to keep apache configuration files installed by a package it configures (ie Roundcubemail) in the first place. They must be removed at install with metadata template.