As far as a standard goes: I've investigated parsers for the "dotenv" format in other languages, and I'm pretty sure no two of them had compatible parsing. Possibly the rust parser was strict enough that it would either parse the same as a shell, or fail to parse.

I have a module about 80% done that would parse all of the variants I found, and allow editing the files without losing order or comments. But of course the last 20% takes too much effort and I haven't found the motivation to complete it.