citadel-webcit software package provides web-based frontend to Citadel groupware server, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install citadel-webcit
citadel-webcit is installed in your system.
Make ensure the citadel-webcit package were installed using the commands given below,
$ sudo dpkg-query -l | grep citadel-webcit *
You will get with citadel-webcit package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Web Software |
| Package | citadel-webcit |
| Version | 902-dfsg-2 |
| Description | web-based frontend to Citadel groupware server |
| Sub Section | Web |