gio:themed-icon-use-default-fallbacks (object)

object -- a g:themed-icon object
setting -- a boolean whether to use default fallbacks

The accessor for the use-default-fallbacks slot of the g:themed-icon class returns whether to use the default fallbacks found by shortening the icon name at '-' characters. If the names list has more than one element, ignores any past the first. For example, if the icon name was "gnome-dev-cdrom-audio", the list would become

'("gnome-dev-cdrom-audio"
  "gnome-dev-cdrom"
  "gnome-dev"
  "gnome")