QGnomeTheme text for QMessageBox::Discard shall not use "Close"

I just stumbled over the fact that in some contexts, the QMessageBox::Discard button is labeled "Close without Saving". I discovered that this wording comes from QGnomeTheme in src/platformsupport/themes/genericunix/qgenericunixthemes.cpp.

Documentation says that I can expect a "A "Discard" or "Don't Save" button, depending on the platform, defined with the DestructiveRole.". There is no mention of "closing". It may have such uses, such as closing a file in an editor window. But the documentation doesn't keep anyone from using Discard in other contexts, such as dealing with intermediate results in an ongoing activity. "Close without Saving" looks strange then.

Either the documentation should give a better warning, or the text should be changed.