I'd take an XML config over a YAML one any day. This isn't to say that XML is great, but its warts are well-known, and they are generally not of the kind that makes it easy to shoot yourself in the foot. Mostly the problem is that it's verbose, and to some extend, redundant.
JSON is also fine, esp. if it is JSON5 (with comments, unquoted keys, and other such minor improvements). I find that braces, brackets, and quotes don't get in the way - if anything, they make the structure clearer.
JSON is also fine, esp. if it is JSON5 (with comments, unquoted keys, and other such minor improvements). I find that braces, brackets, and quotes don't get in the way - if anything, they make the structure clearer.