WebEngine seems to be completely broken on Windows for versions past Qt 5.9. As soon as a web view is opened (e.g. simplebrowser Qt example) I'm getting an exception window for Debug builds showing

ASSERT failure in Q_UNREACHABLE(): "Q_UNREACHABLE was reached", file
C:/Users/qt/work/qt/qtwebengine/src/core/gl_surface_qt.cpp, line 752

and the console output

[11624:2720:0406/111507.984:ERROR:gl_surface_wgl.cc(372)] wglCreatePbufferARB not available.
[11624:2720:0406/111507.984:ERROR:gl_surface_qt.cpp(751)] Requested OpenGL implementation is not supported

In release mode the application just crashes instantly without opening any window.

I'm seeing the same behaviour on 3 different Windows 10 machines with Qt 5.11. Qt 5.10 crashes as well, Qt 5.9 works fine.