In our setup, users have a 256M quota by default on their home directory. That of course is close to 200M, which is the default threshold for kded to throw popups around “you’re low on disk space”. What would be the global file to change this number?
When you do know the users file inside $HOME/.kde4 where it is, then the global one might be somewhere in /usr/share/kde4/services/kded.
Just a guess.