5.8(beta) Default style attributes?

Eeli K

In 5.8 beta the Default style .qml files seem to have something like Default style attributes. Previously the colors were hardcoded, now for example TabButton.qml has:

//! [background]
    background: Rectangle {
        implicitHeight: 40
        color: control.down
            ? (control.checked ? Default.tabButtonCheckedPressedColor : Default.tabButtonPressedColor)
            : (control.checked ? "transparent" : Default.tabButtonColor)
    }
    //! [background]

Is there a way to know and use "Default.tabButtonColor" etc.?

EDIT: Quick Controls 2, of course.

Eeli K

By trial and error I found out that I can

import QtQuick.Controls.impl 2.1

and it works. It's not documented (at least quickly looking at the 5.8 snapshot documentation for styles and styling). I don't know if there are any drawbacks.