Multiple configuration formats

There is a dotenv format for setting environment variables and configuration for the overall system, there's the noosfero.yml format, and probably some other darker/hidden configuration method as well that I haven't stumbled upon.

What were defined as the final method for configuration? I've been very fond of using .env files as they are portable and will work fine using, let's say docker-compose configuration files. But .yml feels more like home for a Rails application.