apt-cache rdepends firefox
firefox
Reverse Depends:
  flashplugin-installer
  xul-ext-bindwood
 |xul-ext-bindwood
 |pytrainer
  mozilla-libreoffice
 |mozilla-libreoffice
 |libreoffice
  xul-ext-webfav
 |xul-ext-webfav
  xul-ext-ubufox
 |xul-ext-ubufox
 |xul-ext-mozvoikko
 |icedtea-plugin
  firefox-gnome-support
  firefox-globalmenu
  firefox-dev
  firefox-dbg
  firefox-branding
  abrowser-branding
  abrowser
 |tiemu
  mythbuntu-desktop
 |gecko-mediaplayer
  flashplugin-installer
  xul-ext-bindwood
 |xul-ext-bindwood
  xubuntu-desktop
 |xsane
 |xfig-doc
 |wysihtml-el
 |wmnetselect
 |webhttrack
  ubuntustudio-desktop
  ubuntu-sugar-remix
  ubuntu-chinese-desktop
  sugar-firefox-activity
  screenlets-pack-basic
  screenlets-pack-all
 |pytrainer
 |nip2
 |mozplugger
 |mozilla-virt-viewer
 |mozilla-plugin-pcmanx
  mozilla-libreoffice
 |mozilla-libreoffice
 |mozilla-gtk-vnc
 |moonlight-plugin-mozilla
 |mediatomb
 |libreoffice
 |libknopflerfish-osgi-java-doc
  gosa-desktop
  gnome-do-plugins
 |gcu-plugin
  firefox-launchpad-plugin
  djvulibre-plugin
 |djvulibre-plugin
 |dhelp
 |deejayd-webui-extension
 |chemical-structures
 |centerim-utf8
 |centerim-fribidi
 |centerim
  cairo-dock-core
 |browser-plugin-packagekit
 |brdesktop-common
 |bluefish
 |ardour
 |amsn
  xul-ext-webfav
 |xul-ext-webfav
  xul-ext-ubufox
 |xul-ext-ubufox
 |xul-ext-mozvoikko
  ubuntu-desktop
 |libjibx1.1-java-doc
  icedtea-plugin
  hunspell-vi
  hunspell-uz
  hunspell-sr
  hunspell-sh
  hunspell-ro
  hunspell-ne
  hunspell-hu
  hunspell-gl-es
  hunspell-fr
  hunspell-eu-es
  hunspell-en-us
  hunspell-en-ca
  hunspell-de-de
  hunspell-de-ch
  hunspell-de-at
  hunspell-da
  firefox-kde-support
  firefox-gnome-support
  firefox-globalmenu
  firefox-dev
  firefox-dbg
  firefox-branding
  abrowser-branding
  abrowser