devmon software package provides virtual package provided by udevil, 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 devmon
devmon is installed in your system.
Make ensure the devmon package were installed using the commands given below,
$ sudo dpkg-query -l | grep devmon*
You will get with devmon package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Virtual packages |
| Package | devmon |
| Version | |
| Description | virtual package provided by udevil |
| Sub Section | Virtual |