Version for Qt Libs like qopcua
I just downloaded and installed https://github.com/qt/qtopcua. Is the branch version supposed to match the Qt version or is that just a coincidence? I have compiled qtopcua version 5.12.2 for use with Qt version 5.12.2.
No, there's no coincidence here. The module is part of the Qt release so it follows the version numbering.
Side note: GitHub is just a mirror, the official repositories are on https://code.qt.io