icu-devtools software package provides Development utilities for International Components for Unicode, 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 icu-devtools
icu-devtools is installed in your system.
Make ensure the icu-devtools package were installed using the commands given below,
$ sudo dpkg-query -l | grep icu-devtools *
You will get with icu-devtools package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Library development |
| Package | icu-devtools |
| Version | 57.1-4 |
| Description | Development utilities for International Components for Unicode |
| Sub Section | libdevel |