Not supporting comments will be a mistake that haunts this API. They give an example of replacing properties files but those do have standardized comments! The proposed pre-processing step means all the comments are lost during round tripping, and the single line comments they suggest are not enough to even match JSONC. By the time those issues have userland workarounds you might as well use another library instead of the built-in one.

This seems to repeat the same mistakes of Go's built in JSON library where the ecosystem is full of workarounds and other libraries that are faster or have better features.