You can uninstall or removes an installed libkonqsidebarplugin4a package itself from Debian 8 (Jessie) through the terminal,
$ sudo apt-get remove libkonqsidebarplugin4a
If you would like to remove libkonqsidebarplugin4a and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove libkonqsidebarplugin4a
If you use with purge options to libkonqsidebarplugin4a package all the configuration and dependent packages will be removed.
$ sudo apt-get purge libkonqsidebarplugin4a
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 libkonqsidebarplugin4a