так как этот участок кода некому поддерживать и привести код к актуальному состоянию.
The window tiling support should be removed from KWin core. This has been discussed on the mailinglist  and the main reasons for removal are currently:
* code is unmaintained and previous developer does not want to work on it any more (asked at Akademy)
* does not support multi-screen
* conflicts with other parts of KWin (activities, tabbing)
* nobody of core dev group uses tiling
There is work going on to get tiling done in a KWin script, which sounds like a good replacement which could make it for 4.10.
Обсуждение в багзилле https://bugs.kde.org/show_bug.cgi?id=303090