emacs25-el software package provides GNU Emacs LISP (.el) 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 emacs25-el
emacs25-el is installed in your system.
Make ensure the emacs25-el package were installed using the commands given below,
$ sudo dpkg-query -l | grep emacs25-el *
You will get with emacs25-el package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Editors |
| Package | emacs25-el |
| Version | 25.1+1-2 |
| Description | GNU Emacs LISP (.el) files |
| Sub Section | Editors |