ctwm software package provides Claudes Tab window manager, 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 ctwm
ctwm is installed in your system.
Make ensure the ctwm package were installed using the commands given below,
$ sudo dpkg-query -l | grep ctwm *
You will get with ctwm package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | X Window System software |
| Package | ctwm |
| Version | 3.7-4 |
| Description | Claudes Tab window manager |
| Sub Section | x11 |