gkrellm-tz software package provides Plugin for gkrellm to show different timezones, 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 gkrellm-tz
gkrellm-tz is installed in your system.
Make ensure the gkrellm-tz package were installed using the commands given below,
$ sudo dpkg-query -l | grep gkrellm-tz *
You will get with gkrellm-tz package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | X Window System software |
| Package | gkrellm-tz |
| Version | 0.8-1 |
| Description | Plugin for gkrellm to show different timezones |
| Sub Section | x11 |