JSON has an advantage of not having significant whitespace: a bit more verbose with the { and [, but I'd argue it is more robust for complex configuration.
YAML feels to me like the creation of a person who has never fought with a makefile that imported another makefile that had an extra tab on line 9432: not quite true hell, but a few hours of trying to figure out WHY things aren't working right you would be hard pressed to tell the difference.
How is "no whitespace" an advantage for a human readable file format? You could write JSON with zero whitespace, but you wouldn't because whitespace is absolutely necessary for human comprehensibility.
As @rockostrich and @fragmede pointed out, I'm talking about whitespace having parsing impact ("significant whitespace"), not just any whitespace. The fact that extra spaces changes the structure of the output seems like a total minefield to me, unless your config is being machine generated (in which case there are many more robust formats to choose).
By "significant", fomojola meant whitespace does not affect parsing. That JSON you linked to could be minified into a single line with 0 whitespace and still be parsed.
YAML feels to me like the creation of a person who has never fought with a makefile that imported another makefile that had an extra tab on line 9432: not quite true hell, but a few hours of trying to figure out WHY things aren't working right you would be hard pressed to tell the difference.