Inexperienced developers might be confused by the OR in there.
In English it sounds like exclusive or, while the whole point of Q_DECLARE_FLAGS is that multiple flags can be set at the same time.

Why not just say "Stores a combination of" ?

I had myself inspired by the wording of https://doc.qt.io/qt-5/qflags.html and similar of Qt docs for flags like https://doc.qt.io/qt-5/qwidget.html#RenderFlag-enum, which currently also talk about
"The QFlags class provides a type-safe way of storing OR-combinations of enum values"
or
"The RenderFlags type is a typedef for QFlags<RenderFlag>. It stores an OR combination of RenderFlag values."

But I tend to think you have a point, the OR here is not really needed and rather confusing, Will update.