Install citadel-doc by entering the following commands in the terminal:
sudo apt update sudo apt install citadel-doc
Description:
complete and feature-rich groupware server (documentation)
This package contains documentation for Citadel, a complete and feature-rich open source groupware platform. . See the 'citadel-server' package for more information.
Homepage: http://www.citadel.org/
Version: 917-2
Section: universe/doc