The following code produces unexpected output when running on Windows 10:

#include <QDebug>
#include <QSysInfo>

int main(int argc, char *argv[])
{
Q_UNUSED(argc);
Q_UNUSED(argv);

// EXPECTED: "Windows 10"
// ACTUAL: "Windows "
qDebug() << QSysInfo::prettyProductName();

return 0;
}

After looking through the Qt sources this appears to be due to the winVer_helper() method in qglobal.cpp not handling the QSysInfo::WV_WINDOWS10 enum value.