To say something concrete about this: it’s vital that JSONSchema have the ability to provide arbitrary namespace-friendly metadata at a field level. This would allow the schema itself to be extended to specify serialization details - much like Kubernetes YAML can go far beyond specifying a deployment and be tagged with various kinds of behavior modifiers.

In theory this is already supported - ish. Because unknown keys at any level of the spec are ignored… but how does one know that those keys will always be unknown? The specification should do something like say certain keys, say, any with a period in the key name, will never be used by the core specification as it evolves. It’s a bit unclear from the spec at https://json-schema.org/draft/2020-12/json-schema-core.html#... IMO. This is why this thread is important!