Steps to reproduce:

• open any Qt application that doesn't save window size and doesn't use a maximized window

Actual results:

• the window opens at position 0,0

Expected results:

• the window is placed by the window manager

I've set KWin to "centered" placement, and with Qt 6.9.2 all new windows appeared at the center of the screen. They now open at the top-left corner, which is not ideal on big displays. I've verified with a non-Qt application that windows are correctly placed by the window manager, so the regression is in Qt.