Set icon.
Sets the terminals icon to icon. If icon is 'none' the request is ignored.
Valid icon names are implementation specific.
If the icon is not found a default icon is used.
🛈 xterm searches for an xpm format image using the following search patterns '%s', '%s.xpm', '%s_48x48', '%s_48x48.xpm'. And then all patterns again with the xpm directory prefixed (default: '/usr/share/pixmaps/').