Essentially a stripped-down ini where you have to code any additional functionality and you will never have any tooling because basic things (like comments) are

Essentially a stripped-down ini where you have to code any additional functionality and you will never have any tooling because basic things (like comments) are not standardized. For the use cases mentioned in the article, I have used JSON with schemas and JSON-merge and JSON-patch quite effectively. VScode supports schemas so it will help you edit the file without making mistakes. You can use JSON merge to combine global and local configs and you could even use custom fields in the schema to indicate metadata, for example, that a key represents an upper limit so the lowest value should be considered when merging.