In licenses such as that of [libjpeg][1] and [freetype][2], there are clauses like the following:

> (2) If only executable code is distributed, then the accompanying
documentation must state that "this software is based in part on the work of
the Independent JPEG Group".


>  o Redistribution in binary form must provide a  disclaimer  that
>  states  that  the software is based in part of the work of the
>  FreeType Team,  in  the  distribution  documentation.

Is putting a notice in a text file in the installation directory enough? Or is a more obvious notice typically needed? For a non-open-source end application, what's the usual way to display these mandatory acknowledgments?