gtk2-engines-sugar software package provides Sugar Learning Platform - GTK+ 2.x theme engine, 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 gtk2-engines-sugar
gtk2-engines-sugar is installed in your system.
Make ensure the gtk2-engines-sugar package were installed using the commands given below,
$ sudo dpkg-query -l | grep gtk2-engines-sugar *
You will get with gtk2-engines-sugar package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Old Libraries |
| Package | gtk2-engines-sugar |
| Version | 0.106.0-1 |
| Description | Sugar Learning Platform - GTK+ 2.x theme engine |
| Sub Section | Oldlibs |