charmap.app software package provides Character map for GNUstep, 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 charmap.app
charmap.app is installed in your system.
Make ensure the charmap.app package were installed using the commands given below,
$ sudo dpkg-query -l | grep charmap.app *
You will get with charmap.app package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | GNUstep |
| Package | charmap.app |
| Version | 0.3~rc1-3 |
| Description | Character map for GNUstep |
| Sub Section | gnustep |