Because we use Symfony we have a mixture of Symfony specific and eZ Publish specific settings in YAML files.

After a discussion with BD concerning some REST v2 settings, I learned that there are certain settings eZ consider should never be changed.
An example here was in security.yml :

            pattern: ^/api/ezp/v2

What settings that developers are not supposed to changed and are settings which need to remain as-is in order for eZ Publish to work properly needs to be documented