It's in their documentation (but a bit hidden): http://doc.qt.io/qt-5/qtwebengine-overview.html#qt-webengine... (This version of Qt WebEngine is based on Chromium version ...).

I usually check their script, which also lets you switch between versions easily: http://code.qt.io/cgit/qt/qtwebengine.git/tree/tools/scripts...

And I also have an overview here: https://github.com/qutebrowser/qutebrowser/blob/master/quteb...