Debian Menu System
Chapter 4 - What packages with applications should do

4.1 Providing a menu file

A package should provide a menu file /usr/share/menu/<package-name> that contains information about each program it likes to make available in the menus.

4.2 Adding a hook for dpkg in your packages

You should add a line like this to your postinst script

      if test -x /usr/bin/update-menus; then update-menus; fi

and the postrm script should get the line

      if test -x /usr/bin/update-menus; then update-menus; fi

(that is, the same line in postinst and in postrm).

Debian Menu System