One of our KWin Effects hasn’t seen much love over the last years and is in fact more broken than working. It’s a pure eye-candy effect which means that it is not at all in the development focus of the KWin team. The truth is, that we are tempted to just delete the effect because we won’t fix it. But of course there are users who like it and would be sad if it gets deleted.
Here you can help: if the issues gets fixed and the effect becomes maintained there is no need to remove it. So if you want to get your hands dirty with a small OpenGL based effect have a look at the Explosion effect and improve it. Have a look at Bug 312176 and all the linked reports to find the issues.