compton-conf software package provides Compton Configurator for Qt, 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 compton-conf
compton-conf is installed in your system.
Make ensure the compton-conf package were installed using the commands given below,
$ sudo dpkg-query -l | grep compton-conf *
You will get with compton-conf package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | X Window System software |
| Package | compton-conf |
| Version | 0.2.0-2 |
| Description | Compton Configurator for Qt |
| Sub Section | x11 |