Finding default icons used by themes
Most of the icons used in themes are part of icon sets, not the themes themselves. You can use any icon set with any theme.
To find the default icons for use with Ambiance:
1) View as text:
You will see
ubuntu-mono-dark listed as the default.
2) Go to
If you browse around the directories, you will Unity specific icons, but not the general application icons.
3) View as text:
Inherits=Humanity-Dark,gnome,hicolor points to the icons.
You can ignore hicolor, which is for accessibility, but the application icons you are looking for are in
/usr/share/icons/Humanity-Dark and 'usr/share/icons/gnome`
Most of the application icons will be in
Themes for Buttons in Dialogs and Similar Objects
These elements are usually called widgets. The creation and use of widgets in code is controlled by a GUI framework. The two most common in Ubuntu are GTK and Qt, but there are others. Widget frameworks allow the programmer to essentially tell the program to, say, show a dialog with confirmation buttons and to then forget about what the buttons will look like because the GUI framework library handles all of that.
Information about how to style widgets is handled through various combinations of CSS files and XML files in the Gtk theme.
The screen shot you included had a a Gedit save dialog, which is a Gtk application.
I'm running 12.10, so the paths and actual files you find may be slightly different, but in
/usr/share/themes/Ambiance where you were before, you want to look mostly in the
The main files you want are:
settings.ini, which gives the default color scheme.
These files will have the color and other information that you are looking for. They may not be easy to interpret, but there is documentation on Gnome interface design and on Gnome theming that may help.
I'm not sure what your ultimate purpose is, but if you are creating an application you can easily use Gtk widgets through a interface designer like Glade and let Gtk do all the work for you.