The generic function
interface-extend-title
is called by the system with an interface and its title before actually displaying the title on the screen. The result must be a string, which is actually displayed. There is no requirement for any relation between the title argument and the result.
The return value string is the title to display on the screen.
The default method uses the values set by set-default-interface-prefix-suffix. You can specialize
interface-extend-title
to get other effects.