[CameronNemo]

>YAML ... do not validate existing json blobs

YAML 1.2 is a strict superset of JSON. What do you mean by "validate" here?

>I would plead that everyone stop using YAML. It's terrible at everything.

Fair enough.

>jsonnet is a template language for a serialization format. Who would choose that nightmare?

People who are tired of Jinja2 and YAML but don't want to jump to a general purpose programming language?

>widespread library support

JSON5 is implemented in Javascript, Go, and C#. Not sure how "widespread" that is. Rust, C, Python, Lua, Java, and Haskell are missing out on the fun.

[westurner]

When I searched for "JSON5 [language]", I found JSON5 implementations in/for Rust, C, Python, Java, and Haskell on the first page of search results.

I like YAML, but some of the syntax conveniences are gotchas: 'no' must be quoted, for example.