/usr/share/themes/Dust/index.theme is in gnome-themes-ubuntu 0.6.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 | [Desktop Entry]
Type=X-GNOME-Metatheme
Name=Dust
Comment=Ubuntu Dust theme
Encoding=UTF-8
[X-GNOME-Metatheme]
GtkTheme=Dust
MetacityTheme=Dust
IconTheme=Humanity-Dark
CursorTheme=DMZ-White
ButtonLayout=maximize,minimize,close:
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