charmap.app software package provides Character map for GNUstep, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) 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 | Ubuntu 16 04 lts xenial xerus |
| Section | X Window System software |
| Package | charmap.app |
| Version | 0.3~rc1-2build1 |
| Description | Character map for GNUstep |
| Sub Section | X88 |