galternatives software package provides graphical setup tool for the alternatives system, 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 galternatives
galternatives is installed in your system.
Make ensure the galternatives package were installed using the commands given below,
$ sudo dpkg-query -l | grep galternatives *
You will get with galternatives package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Administration Utilities |
| Package | galternatives |
| Version | 0.13.5+nmu3 |
| Description | graphical setup tool for the alternatives system |
| Sub Section | admin |