Comment # 3 on bug 1202526 from C J

(In reply to Luciano Santos from comment #1)
> I can confirm that Qt6 apps are still looking like Qt apps rather than
> Gtk-ish ones. Calibre is another example of this.

Here, Calibre is using the default QT dark theme (when Gnome is using the
adwaita dark theme).

But mkvtoolnix.qt6 is using the default light theme (when Gnome is using the
adwaita dark theme)

(As I said, starting it with "mkvtoolnix-gui -style adwaita-dark" applies the
theme properly).