auto-complete-el software package provides intelligent auto-completion extension for GNU Emacs, 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 auto-complete-el
auto-complete-el is installed in your system.
Make ensure the auto-complete-el package were installed using the commands given below,
$ sudo dpkg-query -l | grep auto-complete-el *
You will get with auto-complete-el package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Lisp |
| Package | auto-complete-el |
| Version | 1.3.1-2 |
| Description | intelligent auto-completion extension for GNU Emacs |
| Sub Section | Lisp |