gdb-dbg software package provides GNU Debugger (debug package), 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 gdb-dbg
gdb-dbg is installed in your system.
Make ensure the gdb-dbg package were installed using the commands given below,
$ sudo dpkg-query -l | grep gdb-dbg *
You will get with gdb-dbg package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Debug packages |
| Package | gdb-dbg |
| Version | 7.11.1-2 |
| Description | GNU Debugger (debug package) |
| Sub Section | debug |