fdutils postinst prints the following message:
Note: /usr/bin/fdformat is obsolete and is no longer available.
Please use /usr/bin/superformat instead. Also, there had been some
major changes from version 4.x. Please refer to the documentation.Yet /usr/bin/fdformat which is installed by util-linux can be found in unstable. Am I right? If so, which package, if at all, should be filed a bug against?

