In Qt 4.8 documentation [1] the description of ButtonRole is present, and the links in "See also" and similar places work fine. But in Qt 5.13 [2] the same links lead to nowhere, and search through the documentation page for ButtonRole doesn't reveal the description. 

At the same time, there's a dump of the description (which I found when searching for "The button is invalid", based on the Qt 4.8 docs) in "Member Function Documentation" section, which is clearly a wrong place for this.

This is true for both QMessageBox::ButtonRole and QDialogButtonBox::ButtonRole.

[1]: https://doc.qt.io/archives/qt-4.8/qmessagebox.html#ButtonRole-enum
[2]: https://doc.qt.io/qt-5/qmessagebox.html#ButtonRole-enum