alum:~# dpkg -P iceweasel
dpkg: dependency problems prevent removal of iceweasel:
 iceweasel-gnome-support depends on iceweasel (= 2.0.0.13-0etch1).
 iceweasel-l10n-nb-no depends on iceweasel (>= 2.0.0.11~).
 iceweasel-l10n-nb-no depends on iceweasel (<= 2.1).
 iceweasel-l10n-nb-no depends on iceweasel (>= 2.0.0.11~).
 iceweasel-l10n-nb-no depends on iceweasel (<= 2.1).
dpkg: error processing iceweasel (--purge):
 dependency problems - not removing
Errors were encountered while processing:
 iceweasel