Something like that happened to me yesterday. I reviewed one PR, then some Important Guy came in and said:

• it is nice you reviewed my work, but we need to push this to production right now.
• just fix these things, I described you how. Just copy/paste these snippets
• these are cosmetics, I don’t care
• “cosmetics”, huh? Your shit may just crash
• gfy and push this to production right now
• well, ok

Of course, lack of these “cosmetics” caused crash in production. It’s my fault of course.

I like YAML.

No reason to go beyond simple key-value format like dotenv or just env variables. If you need more structure then maybe you are confusing configuration with state and this is not really the same thing.