gnome-gmail software package provides support for Gmail as the preferred email application in GNOME, 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 gnome-gmail
gnome-gmail is installed in your system.
Make ensure the gnome-gmail package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnome-gmail *
You will get with gnome-gmail package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | GNOME |
| Package | gnome-gmail |
| Version | 2.2-3 |
| Description | support for Gmail as the preferred email application in GNOME |
| Sub Section | gnome |