Version: (using KDE KDE 3.4.92) Open kcontrol and choose KDE Components - Components chooser. Say you want to change default browser. Sometimes you need to pass parameters to the application like URL, Subject, CC... How one could know that %u is used for representing URLs? There isn't written which parameters can be used. 2) the meaning of the option "Open http and https URLs in an app. based on the contents of the URL" is a big mystery for me. It's not documented neither.
There are only a few sections in KDE Components that are documented. I do believe that System Settings is going to replace this, so I know the new documentation will have this covered.
*** This bug has been marked as a duplicate of bug 100016 ***