but the essence of my question is: in which file is stored what desktop environment to load on log in?
pardus wiki or unix/linux administration don't seem to know the term session management... so what term should i use instead?
Sorry for my careless reply..
Well.. There are someway to change your default DE at opening.
1. You may select your default DE manually in your Display Manager (like as gdm)
2. If your Display manager hasn't any choice for DE (like as kdm) , you may find your .dmrc file (a hidden file in your home folder) and change it manually.
3. If you have not .dmrc file or .dmrc file signs session to "default"; pardus xdm (default X DM for pardus), looking into /etc/default/desktop file (in Pardus).. /etc/default/desktop is contained in pardus-default-settings package, and it's default session is kde-plasma.
If you want to return your default pardus kde, you may delete .dmrc
and restart your machine..
but you must control content of "/etc/default/desktop" firstly.