OpenFed is a general-purpose, multilingual Drupal 9 distribution.
It is developed by/for the Belgian Federal Public Service for ICT (Fedict) as part of the Fast2Web offering.
The recommended way to install Openfed is using Composer.
You can use our Openfed Project template like:
composer create-project openfed/openfed-project MY_PROJECT
After that you can just install Openfed like any other distribution.
Openfed <= 11.1.x requires PHP 7.3. Openfed 11.2.x requires PHP 8.1.
You should use, preferably, Drupal.org Openfed issue queue.