I just installed Kubuntu 15.04 and I can't find a single place with systematic description of all available desktop configuration settings. For example, I was setting Screen Locking Timeouts and I found by experiment that setting Lock screen after to 0 is the way to disable it. Another example is Edit application-specific settings: what is the difference between Apply initially and Remember options? Is there a single piece of documentation explaining these issues?
The place for all KDE related User documentation is found at KDE Userbase. If you feel there are changes that should be made based on your experiences, there are a few things you can do, listed in descending order of relevance:
(2) Contact the documentation group via IRC: irc://irc.kde.org/kde-docs
(3) Post a message on the Contributor's Corner section of the KDE Forums asking for the changes to be made or how you can most easily make them.
Help with documentation is ALWAYS needed and appreciated.