base-files software package provides Debian base system miscellaneous files, 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 base-files
base-files is installed in your system.
Make ensure the base-files package were installed using the commands given below,
$ sudo dpkg-query -l | grep base-files *
You will get with base-files package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Administration Utilities |
| Package | base-files |
| Version | 8+deb8u6 |
| Description | Debian base system miscellaneous files |
| Sub Section | admin |