Gtk.Window.prototype.set_icon_name

function set_icon_name(name:String):void {
    // Gjs wrapper for gtk_window_set_icon_name()
}

Sets the icon for the window from a named themed icon. See the docs for Gtk.IconTheme for more details.

Note that this has nothing to do with the WM_ICON_NAME property which is mentioned in the ICCCM.

Since 2.6