$ sudo apt-get remove debconf 

Uninstall debconf including dependent package

If you would like to remove debconf and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove debconf 

Use Purging debconf

If you use with purge options to debconf package all the configuration and dependent packages will be removed.

$ sudo apt-get purge debconf 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove debconf 

See Also,