It would be one feature that gets merged into master. The whole idea behind the flow is to force yourself to make small, incremental changes. We don't want the massive major releases anymore.

Give your customers stable software and enhance it over time. If you aren't ready for a feature to be customer facing, you can always use feature flags to hide it from some or all of your customers in production.

And I agree about your point for hardcoding. If don't wrong it can be disastrous. The point that I was trying to make though is that you don't have to build a full configuration system before going to market. You ultimately might not need configuration at all. Don't add the complexity until absolutely necessary.